Alcohols and Phenols MDCAT Notes, MCQs & Past Papers – Nomenclature, Reactivity, Tests

Q: What is the difference between an alcohol and a phenol?

In alcohols, the –OH group is attached to an sp3-hybridised aliphatic carbon. In phenols, the –OH group is attached directly to an sp2-hybridised carbon of an aromatic benzene ring. This structural difference makes phenols more acidic and more reactive toward electrophilic aromatic substitution.

Q: Why is phenol more acidic than ethanol?

Phenol is more acidic than ethanol because the phenoxide ion (conjugate base) is stabilised by resonance. The negative charge is delocalised into the benzene ring over the ortho and para positions. The ethoxide ion has no such resonance stabilisation, so ethanol is much less acidic (pKa ~16 vs phenol's pKa ~10).

Q: How does the Lucas test distinguish primary, secondary, and tertiary alcohols?

The Lucas test uses concentrated HCl and anhydrous ZnCl2. Tertiary alcohols react immediately (solution turns cloudy due to alkyl chloride formation), secondary alcohols react in 5–10 minutes, and primary alcohols react only on heating or not at all at room temperature. This order reflects the stability of the carbocation intermediate.

Q: What is the FeCl3 test used for?

The FeCl3 test is used to detect the presence of phenols. Phenols form a violet/purple complex with neutral ferric chloride solution. Alcohols do not give this colour, making it a simple way to distinguish between the two classes.

Q: What are the products of oxidation of primary, secondary, and tertiary alcohols?

Primary alcohols are oxidised to aldehydes first and then to carboxylic acids. Secondary alcohols are oxidised to ketones. Tertiary alcohols resist oxidation because they lack a hydrogen atom on the carbon bearing the –OH group (no α-hydrogen).

Q: How is phenol prepared industrially?

Phenol is prepared industrially by the cumene process: benzene is alkylated to cumene (isopropylbenzene), which is oxidised to cumene hydroperoxide and then cleaved with acid to give phenol and acetone.

Q: What is the Williamson ether synthesis?

The Williamson ether synthesis is the reaction of a sodium alkoxide with a primary alkyl halide via an SN2 mechanism to form an ether. It is the most versatile method for preparing both symmetrical and unsymmetrical ethers.

Q: Why do alcohols have higher boiling points than ethers of similar molecular mass?

Alcohols can form intermolecular hydrogen bonds through their –OH group, which requires additional energy to break. Ethers lack an O–H bond and cannot form hydrogen bonds with each other, so their boiling points are lower.

🧪 Chemistry · Alcohols & Phenols

📅 Updated Jan 2026 ⏱️ 30 min read 🎯 High-yield

Alcohols & Phenols — Nomenclature, Reactivity & Tests

Complete MDCAT Chemistry chapter on alcohols and phenols: nomenclature, classification, reactivity, Lucas test, FeCl3 test, acidity, electrophilic aromatic substitution, and more. Includes 150 solved MCQs with explanations and year-wise past papers.

⚡Quick Answers to Common Searches

Direct, snippet-optimized answers to the top questions students search about alcohols and phenols.

What is an alcohol?

An alcohol is an organic compound in which a hydroxyl (–OH) group is bonded to a saturated sp³ carbon. General formula: R–OH. Example: ethanol (CH₃CH₂OH).

What is a phenol?

A phenol is an organic compound in which a hydroxyl (–OH) group is bonded directly to an sp² carbon of a benzene ring. General formula: Ar–OH. Example: phenol (C₆H₅OH).

Difference: alcohol vs phenol?

Alcohols have –OH on sp³ aliphatic carbon; phenols have –OH on sp² aromatic ring. Phenols are more acidic and more reactive toward electrophilic substitution.

Why is phenol more acidic than ethanol?

The phenoxide ion is resonance-stabilised (negative charge delocalised into the ring), while ethoxide is not. Phenol pKa ~10, ethanol pKa ~16.

What is the Lucas test?

Conc. HCl + anhydrous ZnCl₂. 3° alcohols react immediately (cloudy), 2° in 5–10 min, 1° only on heating or not at all.

What is the FeCl₃ test?

Phenols give a violet/purple colour with neutral FeCl₃. Alcohols give no colour. Used to distinguish phenols from alcohols.

Oxidation of alcohols?

1° → aldehyde → carboxylic acid. 2° → ketone. 3° → resistant (no α-H).

What is esterification?

Alcohol + carboxylic acid ⇌ ester + water (acid catalyst, reversible). Alcohol provides the –OH for water.

What is the Williamson synthesis?

Alkoxide + primary alkyl halide → ether (SN2). Best method for unsymmetrical ethers.

Why do alcohols have high boiling points?

They form intermolecular hydrogen bonds through the –OH group. Ethers cannot, so they have lower boiling points.

Phenol + Br₂ water?

Gives a white precipitate of 2,4,6-tribromophenol. No catalyst needed due to strong ring activation by –OH.

What is the iodoform test?

I₂ + NaOH gives yellow CHI₃ precipitate with CH₃CH(OH)– group (ethanol, 2-propanol) and methyl ketones. Distinguishes ethanol from methanol.

Acidity order?

Phenol (pKa ~10) > water (pKa ~15.7) > ethanol (pKa ~16).

Phenol + NaOH?

Phenol reacts with NaOH to form water-soluble sodium phenoxide. Alcohols do not react with NaOH.

What is the cumene process?

Industrial preparation of phenol: benzene → cumene → cumene hydroperoxide → phenol + acetone.

❓People Also Ask — Alcohols & Phenols

Questions students most frequently search about this chapter. Answers are direct and exam-focused.

QWhat is the difference between an alcohol and a phenol?

In alcohols, the –OH group is attached to an sp³-hybridised aliphatic carbon. In phenols, the –OH group is attached directly to an sp²-hybridised carbon of an aromatic benzene ring. This structural difference makes phenols more acidic and more reactive toward electrophilic aromatic substitution.

QWhy is phenol more acidic than ethanol?

Phenol is more acidic than ethanol because the phenoxide ion (conjugate base) is stabilised by resonance. The negative charge is delocalised into the benzene ring over the ortho and para positions. The ethoxide ion has no such resonance stabilisation, so ethanol is much less acidic (pKa ~16 vs phenol's pKa ~10).

QHow does the Lucas test distinguish primary, secondary, and tertiary alcohols?

The Lucas test uses concentrated HCl and anhydrous ZnCl₂. Tertiary alcohols react immediately (solution turns cloudy due to alkyl chloride formation), secondary alcohols react in 5–10 minutes, and primary alcohols react only on heating or not at all at room temperature. This order reflects the stability of the carbocation intermediate.

QWhat is the FeCl₃ test used for?

The FeCl₃ test is used to detect the presence of phenols. Phenols form a violet/purple complex with neutral ferric chloride solution. Alcohols do not give this colour, making it a simple way to distinguish between the two classes.

QWhat are the products of oxidation of primary, secondary, and tertiary alcohols?

Primary alcohols are oxidised to aldehydes first and then to carboxylic acids. Secondary alcohols are oxidised to ketones. Tertiary alcohols resist oxidation because they lack a hydrogen atom on the carbon bearing the –OH group (no α-hydrogen).

QWhat is the mechanism of electrophilic aromatic substitution in phenol?

The –OH group in phenol is strongly activating and ortho/para-directing. It donates electron density into the benzene ring via resonance (+M effect), making the ring more nucleophilic. Electrophiles attack at the ortho and para positions, and the reaction is much faster than with benzene.

QHow is phenol prepared industrially?

Phenol is prepared industrially by the cumene process: benzene is alkylated to cumene (isopropylbenzene), which is oxidised to cumene hydroperoxide and then cleaved with acid to give phenol and acetone.

QWhat is the Williamson ether synthesis?

The Williamson ether synthesis is the reaction of a sodium alkoxide with a primary alkyl halide via an SN2 mechanism to form an ether. It is the most versatile method for preparing both symmetrical and unsymmetrical ethers.

QWhy do alcohols have higher boiling points than ethers of similar molecular mass?

Alcohols can form intermolecular hydrogen bonds through their –OH group, which requires additional energy to break. Ethers lack an O–H bond and cannot form hydrogen bonds with each other, so their boiling points are lower.

QWhat is the reaction of phenol with bromine water?

Phenol reacts rapidly with bromine water to form a white precipitate of 2,4,6-tribromophenol. No catalyst is needed because the –OH group strongly activates the ring. In a non-polar solvent like CS₂ at low temperature, monobromination occurs instead.

QWhat is the acidity order of phenol, water, and ethanol?

The acidity order is phenol (pKa ≈ 10) > water (pKa ≈ 15.7) > ethanol (pKa ≈ 16). Phenol is the strongest acid because its conjugate base is resonance-stabilised.

QWhat are the key differences between alcohols and phenols in their reactions with NaOH and Na metal?

Both react with sodium metal to release hydrogen gas and form alkoxides/phenoxides. However, only phenols react with aqueous NaOH to form a water-soluble salt (sodium phenoxide), because phenol is acidic enough (pKa ~10). Alcohols are not acidic enough to react with NaOH.

QWhat is esterification?

Esterification is the reaction between an alcohol and a carboxylic acid in the presence of an acid catalyst to form an ester and water. The reaction is reversible. The alcohol provides the –OH group that becomes part of the water molecule.

QWhat is the iodoform test used for?

The iodoform test (using I₂ and NaOH) gives a yellow precipitate of iodoform (CHI₃) with alcohols that contain a CH₃CH(OH)– group (e.g., ethanol, 2-propanol) and with methyl ketones. It is used to distinguish ethanol from methanol.

QHow many MCQs come from Alcohols and Phenols in MDCAT?

Alcohols and Phenols typically contribute 2–3 MCQs in MDCAT Chemistry. The chapter is high-yield because questions on acidity, Lucas test, and phenol reactivity are frequently repeated.

QWhat is the product of phenol with Zn dust?

Phenol + Zn dust on heating gives benzene (C₆H₆). This is a reduction reaction where Zn removes the oxygen.

QWhat is the Kolbe-Schmitt reaction?

Sodium phenoxide + CO₂ (under pressure, 125°C) → sodium salicylate → acidification → salicylic acid. Salicylic acid is used to make aspirin.

QWhat is the Reimer-Tiemann reaction?

Phenol + CHCl₃ + KOH → salicylaldehyde (ortho-hydroxybenzaldehyde). The electrophile is dichlorocarbene (:CCl₂).

QWhat are the differences between 1°, 2°, and 3° alcohols?

1°: –OH carbon attached to 1 alkyl group. 2°: attached to 2 alkyl groups. 3°: attached to 3 alkyl groups. Reactivity in SN1 follows 3° > 2° > 1°.

QWhy does phenol not undergo nucleophilic substitution easily?

In phenol, the C–O bond has partial double bond character due to resonance (oxygen lone pair delocalised into the ring). This makes the C–O bond stronger and harder to break in nucleophilic substitution.

📋Syllabus & Learning Outcomes

According to PMDC/PMC MDCAT syllabus, Alcohols and Phenols cover:

Explain nomenclature and structure of alcohols.
Explain the reactivity of alcohols.
Describe the chemistry of alcohols by preparation of ethers and esters.
Explain the nomenclature, structure, and reactivity of phenols.
Discuss the reactivity of phenol and their chemistry by electrophilic aromatic substitution.
Differentiate between an alcohol and a phenol.

📝Full Notes — Alcohols & Phenols

1. Alcohols — Nomenclature & Structure

Functional group: –OH (hydroxyl) attached to sp³ carbon.
General formula: R–OH (alkyl/aliphatic); C_nH_2n+1OH.
Classification:
- 1° (primary): –OH bearing carbon attached to one alkyl group.
- 2° (secondary): –OH bearing carbon attached to two alkyl groups.
- 3° (tertiary): –OH bearing carbon attached to three alkyl groups.
IUPAC: Replace terminal -e of alkane with -ol; number to give –OH lowest. e.g., CH₃–CH₂–OH → ethanol; CH₃–CH(OH)–CH₃ → propan‑2‑ol.
Diols/glycols: two –OH groups; e.g., ethane‑1,2‑diol (ethylene glycol).

2. Reactivity of Alcohols

Polar O–H bond ⇒ weak acidity (pKₐ ~15–18). Alcohols can donate H⁺ to strong bases.
C–O bond can be cleaved under acidic conditions → substitution/elimination.
Oxidation:
- 1° alcohol → aldehyde → carboxylic acid (with strong oxidants like K₂Cr₂O₇/H⁺).
- 2° alcohol → ketone.
- 3° alcohol → resistant to oxidation (no α‑H).
Dehydration: alcohol + conc. H₂SO₄/heat → alkene (E1 mechanism for 2°/3°).
Reaction with active metals (Na, K): alkoxide + H₂ gas.
Lucas test: ZnCl₂/HCl; distinguishes 1°,2°,3° (3° gives immediate turbidity).

3. Ethers & Esters from Alcohols

Ether formation:
- Williamson synthesis: R–O⁻ Na⁺ + R'–X → R–O–R' (best with 1° alkyl halide).
- Intermolecular dehydration of 1° alcohols: 2 R–OH → R–O–R (H₂SO₄, 140°C).
Ester formation (esterification):
- Alcohol + carboxylic acid ⇌ ester + water (Fischer esterification; acid catalyst, usually H₂SO₄).
- Alcohol + acyl chloride → ester + HCl (fast, irreversible).
- Alcohol + acid anhydride → ester + carboxylic acid.
These reactions replace the –OH hydrogen (or the whole –OH) to form new functional groups.

4. Phenols — Nomenclature, Structure & Reactivity

Structure: –OH group directly attached to aromatic ring (sp² C). C₆H₅OH.
Nomenclature: Phenol as parent; substituents numbered; e.g., 2‑methylphenol (o‑cresol).
Acidity: pKₐ ~10 (much stronger acid than alcohols). Phenoxide ion stabilised by resonance.
Reacts with NaOH → sodium phenoxide + H₂O; alcohols do not react with NaOH.
Reacts with active metals, but not with NaHCO₃.

5. Electrophilic Aromatic Substitution in Phenol

–OH is strong activating, ortho/para‑directing.
Bromination: Phenol + Br₂ water → immediate white ppt of 2,4,6‑tribromophenol (no catalyst needed).
Nitration: Dilute HNO₃ → mixture of o‑ and p‑nitrophenol.
Kolbe–Schmitt reaction: Phenoxide + CO₂ → salicylic acid (precursor to aspirin).
Friedel–Crafts acylation: Yields hydroxy ketones.
Because –OH strongly activates ring, phenol undergoes electrophilic substitution much faster than benzene.

6. Distinction: Alcohol vs Phenol

Test	Alcohol	Phenol
NaOH solubility	Not soluble (does not react)	Soluble (forms phenoxide)
NaHCO₃	No reaction	No reaction (too weak an acid)
FeCl₃ test	No colour	Violet/purple complex
Br₂ water	No reaction (light‑induced substitution possible)	White ppt (2,4,6‑tribromophenol)
Oxidation	1°/2° oxidised to carbonyl	Readily oxidised to quinones (complex)

High-Yield Points & Common Traps

Alcohols: 1°,2°,3° classification based on carbon bearing –OH.
Lucas test: 3° alcohol → immediate turbidity; 1° no reaction at room temperature.
Oxidation: 1° → aldehyde → acid; 2° → ketone; 3° resist.
Esterification: alcohol + acid (H⁺ catalyst) ⇌ ester + H₂O (reversible).
Phenol is a stronger acid than alcohol due to resonance stabilisation of phenoxide.
Phenol + Br₂ water → 2,4,6‑tribromophenol (white ppt) – no catalyst needed.
FeCl₃ test: phenol gives violet colour; alcohol no colour.
Phenol is ortho/para directing and strongly activating in electrophilic substitution.
Alcohols do not react with NaOH; phenols do.
Traps: "Phenol is neutral (pH 7)" → False (weakly acidic, pH ~5–6). "Phenol undergoes electrophilic substitution slower than benzene" → False (faster due to –OH activation). "Tertiary alcohol is easily oxidised" → False (resistant).

✅Practice MCQs — Test 1

🧪 Basic Concepts

50 MCQs

1Which of the following is a secondary alcohol?

A. Isobutyl alcohol
B. Isopropyl alcohol
C. Neopentyl alcohol
D. n-butyl alcohol

Answer: B. Isopropyl alcohol

Isopropyl alcohol ((CH₃)₂CHOH) has the OH attached to a carbon that is bonded to two other carbons (secondary). Isobutyl alcohol is primary; neopentyl alcohol is primary; n-butyl alcohol is primary.

2The IUPAC name of the simplest vicinal glycol is:

A. Methanol
B. Ethane-1,1-diol
C. Ethane-1,2-diol
D. Propane-1,2,3-triol

Answer: C. Ethane-1,2-diol

Vicinal glycols have two OH groups on adjacent carbons. The simplest is ethane-1,2-diol (ethylene glycol). Ethane-1,1-diol is a gem-diol (unstable).

3Alcohols have much higher boiling points than ethers of comparable molecular mass because of:

A. Resonance
B. Hydrogen bonding
C. Ionic bonding
D. Van der Waals forces

Answer: B. Hydrogen bonding

Alcohols form intermolecular hydrogen bonds (O-H···O), which require extra energy to break, raising boiling points. Ethers lack O-H bonds and have only dipole-dipole and London forces.

4Which alcohol is also known as 'Wood Spirit'?

A. Ethanol
B. Methanol
C. Ethylene glycol
D. Glycerol

Answer: B. Methanol

Methanol was historically produced by destructive distillation of wood, hence wood spirit.

5In alcohols, the C-O-H bond angle is slightly less than the tetrahedral angle (109.5°) due to:

A. Repulsion between lone pairs of oxygen
B. Bond pair-bond pair repulsion
C. The electronegativity of carbon
D. Lack of hybridization

Answer: A

Oxygen has two lone pairs which exert greater repulsion than bond pairs, compressing the bond angle to about 108.5°.

6Which of the following is most soluble in water?

A. n-Butanol
B. Ethanol
C. Pentanol
D. Hexanol

Answer: B. Ethanol

Solubility decreases as alkyl chain length increases because the non-polar hydrocarbon part dominates. Ethanol (C2) is more soluble than butanol, pentanol, hexanol.

7The general formula for monohydric alcohols is:

A. CₙH₂ₙO
B. CₙH₂ₙ₊₁O
C. CₙH₂ₙ₊₂O
D. CₙH₂ₙ₋₁O

Answer: C. CₙH₂ₙ₊₂O

Monohydric saturated alcohols have formula CₙH₂ₙ₊₂O (e.g., CH₄O for methanol, C₂H₆O for ethanol).

8Which of the following represents a tertiary alcohol?

A. 2-Methyl-1-propanol
B. 2-Methyl-2-propanol
C. 3-Pentanol
D. 2-Butanol

Answer: B. 2-Methyl-2-propanol

2-Methyl-2-propanol ((CH₃)₃COH) has the OH carbon attached to three other carbons (tertiary).

9Which among the following has the highest boiling point?

A. Diethyl ether
B. n-Butane
C. n-Butyl alcohol
D. n-Butyl chloride

Answer: C. n-Butyl alcohol

n-Butyl alcohol has hydrogen bonding, giving highest boiling point among these. Diethyl ether has dipole-dipole but no H-bonding; n-butane only London forces; n-butyl chloride has dipole but no H-bonding.

10Glycerol is a:

A. Monohydric alcohol
B. Dihydric alcohol
C. Trihydric alcohol
D. Phenol

Answer: C. Trihydric alcohol

Glycerol (propane-1,2,3-triol) has three hydroxyl groups → trihydric alcohol.

11When the C-O bond breaks in alcohols, the order of reactivity is:

A. Primary > Secondary > Tertiary
B. Tertiary > Secondary > Primary
C. Secondary > Primary > Tertiary
D. All react at the same rate

Answer: B. Tertiary > Secondary > Primary

Tertiary carbocations are most stable, so tertiary alcohols react fastest in SN1 reactions (C-O bond breaking).

12In the reaction of alcohols with Sodium metal, which bond is broken?

A. C-C
B. C-H
C. O-H
D. C-O

Answer: C. O-H

Sodium reacts with the O-H bond (acidic hydrogen) to form sodium alkoxide and H₂ gas.

13Lucas Reagent is a mixture of:

A. Conc. HCl and anhydrous ZnCl₂
B. Conc. HNO₃ and anhydrous ZnCl₂
C. Conc. HCl and SnCl₂
D. Dil. HCl and ZnCl₂

Answer: A

Lucas reagent: concentrated HCl + anhydrous ZnCl₂. It differentiates alcohols based on rate of formation of alkyl chlorides.

14Which alcohol reacts instantly with Lucas reagent at room temperature?

A. Methanol
B. Ethanol
C. 2-Propanol
D. 2-Methyl-2-propanol

Answer: D. 2-Methyl-2-propanol

Tertiary alcohols (2-methyl-2-propanol) form carbocation rapidly, giving immediate turbidity (alkyl chloride).

15Primary alcohols on oxidation with acidified K₂Cr₂O₇ primarily give:

A. Ketones
B. Ethers
C. Aldehydes
D. Alkanes

Answer: C. Aldehydes

Primary alcohols are first oxidized to aldehydes; further oxidation gives carboxylic acids, but with careful conditions, aldehydes can be isolated.

16Secondary alcohols on oxidation produce:

A. Aldehydes
B. Carboxylic acids
C. Ketones
D. Esters

Answer: C. Ketones

Secondary alcohols have one H on the carbinol carbon, so oxidation gives ketones.

17Tertiary alcohols are resistant to oxidation because:

A. They have no α-hydrogen atom
B. They are too bulky
C. They have very strong C-O bonds
D. They are basic in nature

Answer: A

Oxidation requires removal of hydrogen from the carbinol carbon; tertiary alcohols have no H on that carbon (no α-H), so they resist oxidation.

18The dehydration of ethanol with concentrated H₂SO₄ at 140°C yields:

A. Ethene
B. Diethyl ether
C. Ethyl hydrogen sulfate
D. Ethyne

Answer: B. Diethyl ether

At 140°C, intermolecular dehydration gives diethyl ether. At 170°C, intramolecular gives ethene.

19The reaction between an alcohol and a carboxylic acid in the presence of an acid catalyst is called:

A. Saponification
B. Esterification
C. Hydrogenation
D. Hydration

Answer: B. Esterification

Esterification (Fischer esterification) produces an ester and water.

20Which reagent is used to convert an alcohol into an alkyl chloride with SO₂ and HCl as by-products?

A. PCl₅
B. PCl₃
C. SOCl₂
D. NaCl

Answer: C. SOCl₂

Thionyl chloride (SOCl₂) reacts with alcohol to give alkyl chloride, SO₂, and HCl, both gases, leaving pure product.

21In the Esterification reaction, the OH group is contributed by:

A. The alcohol
B. The carboxylic acid
C. The catalyst
D. Both A and B

Answer: A. The alcohol

The alcohol provides the OH group that becomes part of water; the carboxylic acid provides the H.

22Iodoform test is given by:

A. Methanol
B. Ethanol
C. 1-Propanol
D. n-Butanol

Answer: B. Ethanol

Ethanol and other alcohols with CH₃CH(OH)- group (or methyl ketones) give iodoform test.

23Which of the following will not give the Iodoform test?

A. Ethanol
B. 2-Propanol
C. 3-Pentanol
D. Acetone

Answer: C. 3-Pentanol

3-Pentanol (CH₃CH₂CH(OH)CH₂CH₃) has no CH₃CH(OH)- group; the carbon bearing OH has two ethyl groups, so no iodoform.

24Dehydrogenation of a primary alcohol over heated Copper (300°C) gives:

A. Alkane
B. Alkene
C. Aldehyde
D. Ketone

Answer: C. Aldehyde

Primary alcohols lose H₂ to form aldehydes (RCH₂OH → RCHO + H₂).

25The product of the reaction between Ethanol and PCl₅ is:

A. Ethyl chloride
B. Ethylene dichloride
C. Chloroform
D. Ethyl phosphite

Answer: A. Ethyl chloride

PCl₅ replaces OH with Cl: CH₃CH₂OH + PCl₅ → CH₃CH₂Cl + POCl₃ + HCl.

26Phenol is also known as:

A. Carbolic acid
B. Carbonic acid
C. Benzyl alcohol
D. Salicylic acid

Answer: A. Carbolic acid

Phenol (C₆H₅OH) is also called carbolic acid.

27The C-O bond length in phenol is shorter than in methanol due to:

A. sp³ hybridization of carbon in phenol
B. Partial double bond character via resonance
C. Hydrogen bonding
D. Inductive effect

Answer: B. Partial double bond character via resonance

In phenol, the oxygen lone pair delocalizes into the ring, giving partial double bond character to C-O, shortening the bond.

28Phenol is more acidic than alcohol because:

A. Phenoxide ion is resonance stabilized
B. Phenol has higher molecular weight
C. Phenol is polar
D. Alcohols are more soluble

Answer: A

The phenoxide ion is stabilized by resonance with the aromatic ring, making phenol more acidic than aliphatic alcohols.

29Which of the following is most acidic?

A. Phenol
B. Ethanol
C. p-Nitrophenol
D. p-Methylphenol

Answer: C. p-Nitrophenol

p-Nitrophenol has an electron-withdrawing nitro group that stabilizes the phenoxide ion, increasing acidity.

30Phenol reacts with Bromine water to give a white precipitate of:

A. 2-Bromophenol
B. 4-Bromophenol
C. 2,4,6-Tribromophenol
D. Bromobenzene

Answer: C. 2,4,6-Tribromophenol

Phenol is highly activated; bromine water causes multiple substitution at ortho and para positions, giving 2,4,6-tribromophenol (white precipitate).

31The reaction of phenol with Zn dust on heating yields:

A. Benzene
B. Cyclohexane
C. Zinc phenoxide
D. Benzaldehyde

Answer: A. Benzene

Zn dust reduces phenol to benzene: C₆H₅OH + Zn → C₆H₆ + ZnO.

32Nitration of phenol with dilute HNO₃ at room temperature yields:

A. Picric acid
B. o- and p-Nitrophenol
C. m-Nitrophenol
D. Nitrobenzene

Answer: B. o- and p-Nitrophenol

Dilute HNO₃ at low temperature gives a mixture of ortho and para nitrophenols.

33Picric acid is chemically:

A. 2,4,6-Trinitrophenol
B. 2,4-Dinitrophenol
C. Trinitrotoluene
D. 2,4,6-Tribromophenol

Answer: A. 2,4,6-Trinitrophenol

Picric acid is 2,4,6-trinitrophenol, used as an explosive and dye.

34Phenol reacts with FeCl₃ to give:

A. Red color
B. Green color
C. Violet color
D. White precipitate

Answer: C. Violet color

Phenols give a violet/blue color with neutral FeCl₃ due to complex formation.

35The substitution of an -OH group in phenol by an Electrophile occurs at:

A. Meta position
B. Ortho and Para positions
C. Only Para position
D. Only Meta position

Answer: B. Ortho and Para positions

The -OH group is strongly activating and ortho/para directing due to resonance donation.

36Kolbe's reaction is used to prepare:

A. Benzene
B. Salicylic acid
C. Picric acid
D. Aspirin

Answer: B. Salicylic acid

Kolbe-Schmitt reaction: sodium phenoxide + CO₂ → sodium salicylate, then acidification gives salicylic acid.

37Phenol is less acidic than:

A. Ethanol
B. Water
C. Acetic acid
D. Methanol

Answer: C. Acetic acid

Acetic acid (pKa ≈ 4.76) is much stronger than phenol (pKa ≈ 10). Ethanol and methanol have pKa ~16, water ~15.7.

38Bakelite is a polymer of:

A. Phenol and Formaldehyde
B. Phenol and Acetaldehyde
C. Phenol and Benzene
D. Ethanol and Phenol

Answer: A. Phenol and Formaldehyde

Bakelite is a thermosetting polymer from phenol and formaldehyde.

39Hydrogenation of Phenol in the presence of Nickel at 150°C yields:

A. Benzene
B. Cyclohexanol
C. n-Hexane
D. Cyclohexane

Answer: B. Cyclohexanol

Catalytic hydrogenation of phenol gives cyclohexanol (C₆H₁₁OH).

40When phenol is treated with excess Bromine in CS₂ at low temperature, the product is:

A. 2,4,6-Tribromophenol
B. Mixture of o- and p-bromophenol
C. m-Bromophenol
D. Bromobenzene

Answer: B. Mixture of o- and p-bromophenol

In non-polar solvent (CS₂) at low temperature, bromination stops at monobromophenol (mainly p- and o-).

41Which test is used to distinguish between Ethanol and Methanol?

A. Lucas test
B. Iodoform test
C. FeCl₃ test
D. Tollens' test

Answer: B. Iodoform test

Ethanol gives iodoform test (yellow precipitate), methanol does not. Lucas test differentiates based on reactivity, but both are primary and react slowly.

42Alcohol and Phenol can be distinguished by using:

A. Sodium metal
B. PCl₅
C. FeCl₃ solution
D. Lucas reagent

Answer: C. FeCl₃ solution

Phenol gives violet color with FeCl₃, alcohols do not.

43Which of the following will react with NaOH?

A. Ethanol
B. Phenol
C. Diethyl ether
D. n-Butanol

Answer: B. Phenol

Phenol is acidic enough to react with NaOH to form sodium phenoxide; aliphatic alcohols are weaker acids and do not react with NaOH.

44The correct order of acidity is:

A. Water > Ethanol > Phenol
B. Phenol > Water > Ethanol
C. Ethanol > Water > Phenol
D. Water > Phenol > Ethanol

Answer: B. Phenol > Water > Ethanol

Phenol (pKa ~10) > Water (pKa ~15.7) > Ethanol (pKa ~16).

45Ethers are isomers of:

A. Alcohols
B. Ketones
C. Aldehydes
D. Esters

Answer: A. Alcohols

Ethers have same molecular formula as alcohols (e.g., C₂H₆O: ethanol and dimethyl ether).

46Rectified spirit contains:

A. 95% Ethanol
B. 100% Ethanol
C. 50% Ethanol
D. 5% Ethanol

Answer: A. 95% Ethanol

Rectified spirit is about 95% ethanol and 5% water (azeotrope).

47Williamson synthesis is used for the preparation of:

A. Alcohols
B. Ethers
C. Phenols
D. Alkanes

Answer: B. Ethers

Williamson synthesis: alkyl halide + sodium alkoxide → symmetrical or unsymmetrical ether.

48Which of the following is a primary alcohol?

A. 2-Butanol
B. 2-Methyl-2-propanol
C. 2,2-Dimethyl-1-propanol
D. Isopropyl alcohol

Answer: C. 2,2-Dimethyl-1-propanol

2,2-Dimethyl-1-propanol (neopentyl alcohol) has OH on a primary carbon (CH₂OH).

49Reaction of Phenol with NaOH followed by CH₃I yields:

A. Anisole
B. Toluene
C. Benzyl alcohol
D. Ethyl benzene

Answer: A. Anisole

Phenol → sodium phenoxide → with methyl iodide gives anisole (methyl phenyl ether).

50Which of the following is not a characteristic of phenols?

A. They are acidic in nature
B. They give FeCl₃ test
C. They are easily oxidized to aldehydes
D. They undergo electrophilic substitution easily

Answer: C. They are easily oxidized to aldehydes

Phenols are not easily oxidized to aldehydes; they can be oxidized to quinones. Alcohols are oxidized to aldehydes/ketones.

✅Practice MCQs — Test 2

🧪 Advanced Concepts

50 MCQs

1Which of the following alcohols is most resistant to oxidation even under drastic conditions?

A. 2,2-Dimethyl-1-propanol
B. 2-Methyl-2-butanol
C. 3-Pentanol
D. Isopropyl alcohol

Answer: B. 2-Methyl-2-butanol

2-Methyl-2-butanol is a tertiary alcohol; it has no α-hydrogen on the carbinol carbon, so it resists oxidation.

2The C-O-H bond angle in methanol is 108.9°. What is the most accurate reason for it being less than 109.5°?

A. sp² hybridization of oxygen
B. lp-lp repulsion of oxygen being greater than bp-bp repulsion
C. The high electronegativity of the Methyl group
D. Steric hindrance of the Hydroxyl group

Answer: B

Lone pair-lone pair repulsion on oxygen is greater than bond pair-bond pair repulsion, compressing the bond angle.

3Which of the following isomers of C₄H₁₀O possesses a chiral center?

A. n-Butanol
B. Isobutanol
C. sec-Butyl alcohol
D. tert-Butyl alcohol

Answer: C. sec-Butyl alcohol

sec-Butyl alcohol (2-butanol) has a chiral carbon at C2 (attached to OH, H, CH₃, C₂H₅).

4Arrange the following in increasing order of boiling points: I. n-Butane, II. Ethanol, III. Water, IV. Ethylene glycol

A. I < II < III < IV
B. I < III < II < IV
C. IV < III < II < I
D. II < I < III < IV

Answer: A

Boiling point increases with hydrogen bonding and molecular weight: n-butane (no H-bond) lowest, then ethanol (H-bond but small), then water (two H-bonds per molecule), then ethylene glycol (two OH groups, extensive H-bonding).

5In the structure of Phenol, the Carbon atom attached to the Oxygen atom is:

A. sp³ hybridized
B. sp² hybridized
C. sp hybridized
D. Unhybridized

Answer: B. sp² hybridized

The carbon of the benzene ring is sp² hybridized.

6The dipole moment of phenol is smaller than that of methanol. This is primarily due to:

A. The +I effect of the phenyl group
B. The -I effect and +R effect of the -OH group on the ring
C. Phenol being more acidic
D. Hydrogen bonding in methanol being stronger

Answer: B

In phenol, the oxygen lone pair is partially delocalized into the ring, reducing the net dipole moment compared to methanol where lone pairs are more localized.

7Which among these is a 'Trihydric' alcohol?

A. Ethylene glycol
B. Benzyl alcohol
C. Glycerol
D. Catechol

Answer: C. Glycerol

Glycerol has three OH groups; ethylene glycol is dihydric; benzyl alcohol is monohydric; catechol (1,2-dihydroxybenzene) is a dihydric phenol.

8Neopentyl alcohol reacts with HCl/ZnCl₂ to form 2-chloro-2-methylbutane. This occurs via:

A. SN2 mechanism
B. SN1 mechanism with Methyl shift
C. E2 mechanism
D. SN1 mechanism with Hydride shift

Answer: B

Neopentyl carbocation (primary) rearranges via methyl shift to a more stable tertiary carbocation, then Cl⁻ attacks.

9The solubility of alcohols in water decreases with an increase in molecular mass because:

A. The polar nature of the -OH group increases
B. The non-polar hydrocarbon part becomes dominant
C. The number of Hydrogen bonds per molecule increases
D. Density decreases

Answer: B

As the alkyl chain lengthens, the hydrophobic effect dominates, reducing water solubility.

10Which of the following alcohols has the highest heat of combustion?

A. Methanol
B. Ethanol
C. n-Propanol
D. n-Butanol

Answer: D. n-Butanol

Heat of combustion increases with number of carbon atoms; n-butanol has the highest among these.

11In the reaction of ROH + HX → RX + H₂O, the order of reactivity of HX is:

A. HCl > HBr > HI
B. HI > HBr > HCl
C. HBr > HI > HCl
D. HI > HCl > HBr

Answer: B

HI is strongest acid and best nucleophile (I⁻ is good leaving group), so fastest. HCl is weakest acid, slowest.

12The dehydration of 2-Butanol with conc. H₂SO₄ at 170°C yields 'But-2-ene' as the major product. This follows:

A. Hofmann Rule
B. Saytzeff Rule
C. Markownikov's Rule
D. Anti-Markownikov's Rule

Answer: B. Saytzeff Rule

Saytzeff rule: more substituted alkene (2-butene) is major product.

13Which reagent provides the best yield for converting a primary alcohol into an alkyl chloride without interfering side-reactions?

A. PCl₅
B. PCl₃
C. SOCl₂ in Pyridine
D. HCl/ZnCl₂

Answer: C

SOCl₂ in pyridine gives clean conversion with gaseous byproducts; pyridine acts as base to neutralize HCl.

14When ethanol is treated with an excess of H₂SO₄ at 180°C, the gas evolved is:

A. Ethane
B. Ethene
C. Diethyl ether
D. Carbon dioxide

Answer: B. Ethene

At 180°C, intramolecular dehydration gives ethene (gas).

15The reaction of an alcohol with Thionyl Chloride (SOCl₂) in the absence of pyridine usually proceeds with:

A. Inversion of configuration (SN2)
B. Retention of configuration (SNi)
C. Racemization
D. Elimination

Answer: B

Without pyridine, the reaction proceeds via an SNi mechanism (internal nucleophilic substitution) with retention of configuration.

16In the esterification of CH₃CH₂OH with CH₃COOH using isotopic Oxygen (¹⁸O) in alcohol, the isotope appears in:

A. Water
B. The Ester
C. Both water and ester
D. The acid

Answer: B. The Ester

The ¹⁸O from alcohol ends up in the ester (RCO¹⁸OCH₂CH₃), not in water (which comes from OH of acid).

17A compound 'X' with formula C₃H₈O on oxidation gives 'Y' (C₃H₆O). 'Y' gives a positive Iodoform test. 'X' is:

A. 1-Propanol
B. 2-Propanol
C. Methyl ethyl ether
D. Propionaldehyde

Answer: B. 2-Propanol

Oxidation of 2-propanol gives acetone (C₃H₆O), which gives iodoform test. 1-propanol gives propanal (no iodoform).

18Which of the following alcohols is least likely to be dehydrated?

A. 2-Methyl-2-propanol
B. Ethanol
C. Methanol
D. 2-Propanol

Answer: C. Methanol

Methanol has no β-hydrogens, so cannot undergo β-elimination to form an alkene.

19Acid-catalyzed hydration of an alkene to produce an alcohol involves the formation of:

A. Free radical
B. Carbanion
C. Carbocation
D. Carbene

Answer: C. Carbocation

The mechanism proceeds via protonation of alkene to form a carbocation intermediate, then water attacks.

20Which alcohol will give a yellow precipitate with I₂/NaOH?

A. 3-Pentanol
B. 2-Pentanol
C. 1-Pentanol
D. 2,2-Dimethyl-1-propanol

Answer: B. 2-Pentanol

2-Pentanol has a CH₃CH(OH)- group, so gives iodoform. 3-Pentanol has OH on C3 with no methyl group on that carbon.

21R-CH₂-OH → R-CHO. The best reagent for this conversion is:

A. K₂Cr₂O₇ / H⁺
B. KMnO₄ / OH⁻
C. PCC (Pyridinium Chlorochromate)
D. O₃

Answer: C

PCC is a mild oxidizing agent that stops at aldehyde, avoiding overoxidation to carboxylic acid.

22The reaction of 1-propanol with Sodium metal releases H₂ gas. This demonstrates:

A. The basic nature of alcohol
B. The acidic nature of alcohol
C. The oxidizing nature of alcohol
D. The reducing nature of alcohol

Answer: B. The acidic nature of alcohol

Alcohols are weak acids; they react with sodium metal to liberate H₂, showing acidic behavior.

23Which of the following will result in the formation of a tertiary alcohol?

A. Formaldehyde + Grignard Reagent
B. Acetaldehyde + Grignard Reagent
C. Acetone + Grignard Reagent
D. Ethylene oxide + Grignard Reagent

Answer: C. Acetone + Grignard Reagent

Acetone (R₂C=O) + Grignard gives tertiary alcohol after hydrolysis.

24When tert-butyl alcohol is passed over heated Copper at 300°C, the product is:

A. 2-Methylpropene (Isobutylene)
B. 2-Methylpropanal
C. Propanone
D. Butane

Answer: A. 2-Methylpropene

Dehydrogenation of tertiary alcohols over Cu leads to elimination (alkene) rather than aldehyde/ketone.

25The cleavage of C-O bond in alcohols occurs most easily in:

A. CH₃OH
B. (CH₃)₂CHOH
C. (CH₃)₃COH
D. CH₃CH₂OH

Answer: C. (CH₃)₃COH

Tertiary alcohols form the most stable carbocation upon C-O cleavage, so easiest.

26Which of the following has the lowest pKa value?

A. Phenol
B. m-Nitrophenol
C. o-Nitrophenol
D. p-Nitrophenol

Answer: D. p-Nitrophenol

p-Nitrophenol has the strongest acidity (lowest pKa) due to strong -I and -M effects of NO₂ at para position, stabilizing phenoxide.

27Phenol is treated with Br₂ in H₂O and Br₂ in CS₂ separately. The products are respectively:

A. 2,4,6-Tribromophenol and p-Bromophenol
B. p-Bromophenol and 2,4,6-Tribromophenol
C. m-Bromophenol and o-Bromophenol
D. 2,4,6-Tribromophenol and m-Bromophenol

Answer: A

In polar solvent (water), phenoxide ion forms, leading to tribromo. In non-polar CS₂, monobromination occurs (mainly para).

28In the Reimer-Tiemann reaction, the electrophile that attacks the phenoxide ion is:

A. :CCl₂ (Dichlorocarbene)
B. CHCl₃
C. Cl⁺
D. CCl₃⁻

Answer: A. :CCl₂ (Dichlorocarbene)

Dichlorocarbene (:CCl₂) is generated from CHCl₃ and base, and it attacks the ortho position of phenoxide.

29The reaction of phenol with phthalic anhydride in the presence of H₂SO₄ produces:

A. Aspirin
B. Phenolphthalein
C. Methyl salicylate
D. Bakelite

Answer: B. Phenolphthalein

Phenol + phthalic anhydride → phenolphthalein (indicator).

30Arrange the following in decreasing order of acidity: I. Phenol, II. p-Cresol, III. m-Nitrophenol, IV. p-Nitrophenol

A. IV > III > I > II
B. III > IV > I > II
C. IV > III > II > I
D. I > II > III > IV

Answer: A

Electron-withdrawing NO₂ increases acidity, especially at para. p-Cresol (methyl, electron-donating) is less acidic than phenol.

31Phenol does not undergo substitution of the -OH group by Cl using HCl because:

A. The C-O bond has partial double bond character due to resonance
B. Phenol is more basic than alcohols
C. The Phenyl carbocation is highly stable
D. The -OH group is a good leaving group in phenol

Answer: A

The C-O bond in phenol has partial double bond character (resonance), making it stronger and less reactive towards nucleophilic substitution.

32When Phenol is oxidized with Chromyl chloride (Na₂Cr₂O₇ / H₂SO₄), the product is:

A. Benzoic acid
B. p-Benzoquinone
C. Catechol
D. Quinol

Answer: B. p-Benzoquinone

Oxidation of phenol with chromic acid gives p-benzoquinone.

33The reaction: Phenol + NaOH → Sodium Phenoxide → under CO₂ at 125°C, then acidification gives:

A. Salicylaldehyde
B. Salicylic acid
C. Benzoic acid
D. Picric acid

Answer: B. Salicylic acid

Kolbe-Schmitt reaction: sodium phenoxide + CO₂ → sodium salicylate → salicylic acid.

34Phenol is more reactive than benzene towards electrophilic substitution because:

A. -OH group is electron-withdrawing by induction
B. -OH group is electron-donating by resonance
C. Phenol is acidic
D. The ring is deactivated

Answer: B

The -OH group donates electrons by resonance (+M effect), activating the ring toward electrophiles.

35The conversion of Phenol to Aspirin involves:

A. Reimer-Tiemann reaction
B. Kolbe's reaction followed by Acetylation
C. Nitration followed by Reduction
D. Oxidation followed by Esterification

Answer: B

Phenol → salicylic acid (Kolbe) → acetylation with acetic anhydride gives aspirin.

36Which of the following does NOT react with Phenol?

A. NaOH
B. NaHCO₃
C. FeCl₃
D. Na metal

Answer: B. NaHCO₃

Phenol is not acidic enough to react with NaHCO₃ (pKa ~10 vs H₂CO₃ pKa ~6.4).

37The major product of nitration of phenol with concentrated HNO₃/H₂SO₄ is:

A. 2-Nitrophenol
B. 4-Nitrophenol
C. 2,4,6-Trinitrophenol
D. m-Nitrophenol

Answer: C. 2,4,6-Trinitrophenol

Concentrated nitrating mixture causes multiple nitration, giving picric acid (2,4,6-trinitrophenol).

38Dow's process involves the conversion of Chlorobenzene to Phenol using:

A. NaOH at 360°C and 150 atm
B. H₂O at 100°C
C. FeCl₃ and HCl
D. NH₃ and Cu₂O

Answer: A

Chlorobenzene + NaOH (high temperature and pressure) → sodium phenoxide → acidification gives phenol.

39Phenoxide ion is more stable than Phenol because:

A. It has more resonance structures
B. In Phenol, resonance involves charge separation while in phenoxide it doesn't
C. Oxygen is more electronegative in the ion
D. Phenol is a gas

Answer: B

In phenol, resonance structures involve charge separation (C⁺-O⁻), while in phenoxide, all structures have negative charge on oxygen (more stable).

40Friedel-Crafts alkylation of Phenol usually gives low yields because:

A. The -OH group deactivates the ring
B. The AlCl₃ catalyst coordinates with the Oxygen lone pair
C. Phenol is too acidic for AlCl₃
D. The reaction is too slow

Answer: B

AlCl₃ complexes with the oxygen of phenol, deactivating the ring and consuming catalyst.

41Which of the following will produce a violet color with neutral FeCl₃?

A. Benzyl alcohol
B. Cyclohexanol
C. o-Cresol
D. Ethanol

Answer: C. o-Cresol

Phenols (including cresols) give violet color with FeCl₃; aliphatic alcohols do not.

42An organic compound 'A' reacts with Sodium to liberate H₂ and forms 'B' with FeCl₃. 'A' is:

A. Ethanol
B. Phenol
C. Acetic acid
D. Diethyl ether

Answer: B. Phenol

Phenol reacts with Na to give H₂ and with FeCl₃ gives violet color. Ethanol gives H₂ but no FeCl₃ test.

43Which test can distinguish between 2-Pentanol and 3-Pentanol?

A. Lucas test
B. Iodoform test
C. FeCl₃ test
D. Bromine water test

Answer: B. Iodoform test

2-Pentanol has CH₃CH(OH)- group, gives iodoform test; 3-Pentanol does not.

44The product of the reaction between Phenol and Benzene diazonium chloride in alkaline medium is:

A. Benzene
B. Chlorobenzene
C. p-Hydroxyazobenzene (Orange dye)
D. Aniline

Answer: C

Coupling reaction gives azo dye (p-hydroxyazobenzene).

45Which of the following is the strongest acid?

A. Cl-CH₂-CH₂-OH
B. F-CH₂-CH₂-OH
C. O₂N-CH₂-CH₂-OH
D. CH₃-CH₂-OH

Answer: C

Electron-withdrawing groups increase acidity; NO₂ is strongest -I group among these, making O₂N-CH₂CH₂OH most acidic.

46What happens when Glycerol is heated with KHSO₄?

A. It forms Acrolein
B. It forms Oxalic acid
C. It forms Allyl alcohol
D. It forms Glyceraldehyde

Answer: A. Acrolein

Dehydration of glycerol with KHSO₄ gives acrolein (CH₂=CH-CHO).

47The denaturation of alcohol is done by adding:

A. Methanol and Pyridine
B. Water
C. Sugar
D. Acetic acid

Answer: A

Denatured alcohol contains methanol (toxic) and pyridine (bad smell) to make it unfit for drinking.

48Lucas test is based on the difference in:

A. Acidity of alcohols
B. Basicity of alcohols
C. Rate of formation of alkyl chlorides
D. Rate of oxidation of alcohols

Answer: C

Lucas test measures the rate of formation of alkyl chlorides; tertiary > secondary > primary.

49Reaction of Phenol with Excess Conc. HNO₃ yields Picric acid. The yield is often low due to:

A. Nitration of the meta position
B. Oxidation of the phenolic ring
C. Formation of Nitrobenzene
D. Evaporation of Phenol

Answer: B

Concentrated HNO₃ can oxidize the phenol ring, reducing yield.

50In the following reaction sequence: Ethanol → PCl₅ → A → alc. KOH → B → H₂O/H⁺ → C. What is 'C'?

A. Ethane
B. Ethanol
C. Ethene
D. Ethyl hydrogen sulfate

Answer: B. Ethanol

Ethanol → chloroethane (A) → ethene (B) → hydration gives ethanol (C).

✅Practice MCQs — Test 3

🧪 Exam-Level Questions

50 MCQs

1In the acid-catalyzed dehydration of 3,3-dimethyl-2-butanol, the major product is 2,3-dimethyl-2-butene. This is due to:

A. A 1,2-hydride shift forming a more stable tertiary carbocation
B. A 1,2-methyl shift forming a more stable tertiary carbocation
C. An E2 mechanism preventing rearrangement
D. The formation of a primary carbocation as an intermediate

Answer: B

Initial carbocation at C2 is secondary; a methyl shift from C3 to C2 gives a tertiary carbocation, leading to the more stable alkene.

2Which of the following compounds has the highest pKa value (is the weakest acid)?

A. 2,2,2-Trifluoroethanol
B. 2-Chloroethanol
C. Ethanol
D. Isopropanol

Answer: D. Isopropanol

Isopropanol (secondary) is slightly less acidic than ethanol due to +I effect of methyl groups. Electron-withdrawing groups (F, Cl) increase acidity (lower pKa).

3What is the stereochemical outcome of the reaction between (S)-2-Bromobutane and NaOH via SN2 mechanism?

A. (R)-2-Butanol (100% inversion)
B. (S)-2-Butanol (100% retention)
C. Racemic mixture of 2-Butanol
D. (R)-2-Bromobutane

Answer: A

SN2 proceeds with inversion of configuration; (S)-bromide gives (R)-alcohol.

4Which alcohol will undergo the fastest SN1 reaction with concentrated HBr?

A. 1-Butanol
B. 2-Butanol
C. 2-Methyl-2-propanol
D. 2-Methyl-1-propanol

Answer: C. 2-Methyl-2-propanol

Tertiary alcohol (2-methyl-2-propanol) forms most stable carbocation, fastest SN1.

5In the molecule of Phenol, the lone pair of electrons on Oxygen is involved in resonance. How does this affect the C-O bond compared to Methanol?

A. It increases the bond length and decreases bond strength
B. It decreases the bond length and increases bond strength
C. It makes the bond purely ionic
D. It has no effect on bond length

Answer: B

Partial double bond character shortens and strengthens the C-O bond in phenol vs methanol.

6Hydroboration-Oxidation of 1-Methylcyclopentene yields:

A. trans-2-Methylcyclopentanol
B. cis-2-Methylcyclopentanol
C. 1-Methylcyclopentanol
D. 2-Methylcyclopentane

Answer: B

Hydroboration-oxidation gives anti-Markovnikov addition with syn stereochemistry, leading to the cis isomer (OH and methyl cis).

7Which of the following describes the 'Glycerol' molecule correctly regarding its IUPAC priority?

A. Propane-1,2,3-triol
B. 1,2,3-Trihydroxypropane
C. Glycerin-1,2,3-triol
D. Propyl trioxide

Answer: A

IUPAC name is propane-1,2,3-triol.

8The reaction of an epoxide (ethylene oxide) with a Grignard reagent (RMgX) followed by hydrolysis yields:

A. Secondary alcohol with two extra carbons
B. Primary alcohol with two extra carbons
C. Tertiary alcohol with one extra carbon
D. Primary alcohol with one extra carbon

Answer: B

Epoxide ring opening with RMgX gives primary alcohol with two extra carbons (R-CH₂-CH₂-OH).

9Which of the following is most soluble in a 1% NaOH solution?

A. Benzyl alcohol
B. Cyclohexanol
C. p-Cresol
D. n-Hexanol

Answer: C. p-Cresol

p-Cresol is a phenol, reacts with NaOH to form water-soluble phenoxide. Benzyl alcohol and cyclohexanol are neutral alcohols, less soluble.

10The formation of an intramolecular hydrogen bond is most prominent in:

A. o-Nitrophenol
B. p-Nitrophenol
C. m-Nitrophenol
D. Phenol

Answer: A. o-Nitrophenol

Ortho isomer allows hydrogen bonding between -OH and -NO₂ (or -OH and -OH), reducing intermolecular H-bonding and lowering melting point.

11During the Esterification of a bulky alcohol like tert-butyl alcohol with acetic acid, the rate is significantly slower than methanol. This is due to:

A. Electronic repulsion
B. Steric hindrance in the tetrahedral intermediate
C. The lower acidity of tertiary alcohols
D. The stability of the tert-butyl carbocation

Answer: B

The tetrahedral intermediate in esterification is sterically hindered by the bulky tert-butyl group, slowing the reaction.

12What is the intermediate formed during the Reimer-Tiemann reaction of phenol with CHCl₃/KOH?

A. Carbonium ion
B. Carbanion
C. Dichlorocarbene
D. Nitrene

Answer: C. Dichlorocarbene

Dichlorocarbene (:CCl₂) is the electrophilic intermediate.

13Which reagent can selectively oxidize a primary alcohol to a carboxylic acid without stopping at the aldehyde?

A. PCC in CH₂Cl₂
B. Jones Reagent (CrO₃ / H₂SO₄)
C. MnO₂
D. Cu at 300°C

Answer: B

Jones reagent (chromic acid) is strong enough to overoxidize primary alcohols to carboxylic acids.

14Reaction of Phenol with CO₂ and NaOH at high pressure (Kolbe-Schmitt) primarily gives Salicylic acid. If the temperature is raised above 140°C, what is the likely minor byproduct?

A. p-Hydroxybenzoic acid
B. m-Hydroxybenzoic acid
C. Phthalic acid
D. Benzene

Answer: A

At higher temperatures, para substitution becomes significant, giving p-hydroxybenzoic acid.

15The reaction of 2,2-dimethyl-1-propanol with HCl/ZnCl₂ yields 2-chloro-2-methylbutane. The rate-determining step involves:

A. Formation of a primary carbocation
B. Formation of a secondary carbocation
C. Formation of a tertiary carbocation via methyl shift
D. Departure of the water molecule from the oxonium ion

Answer: C

The primary carbocation rearranges via methyl shift to a tertiary carbocation, which then captures Cl⁻.

16In the reaction of glycol (CH₂OH-CH₂OH) with periodic acid (HIO₄), the products are:

A. Two moles of Formaldehyde
B. One mole of Glyoxal
C. Two moles of Formic acid
D. Methanol and Formic acid

Answer: A

Periodic acid cleaves vicinal diols to carbonyl compounds; ethylene glycol gives two molecules of formaldehyde.

17Which of the following phenols is the STRONGEST acid?

A. 2,4,6-Trinitrophenol
B. 2,4-Dinitrophenol
C. 3,5-Dinitrophenol
D. 4-Nitrophenol

Answer: A. 2,4,6-Trinitrophenol

Picric acid (2,4,6-trinitrophenol) is most acidic due to three strong electron-withdrawing nitro groups.

18Azeotropic distillation is used to obtain 100% absolute alcohol from rectified spirit by adding:

A. Benzene
B. Ether
C. Chloroform
D. Glycerol

Answer: A. Benzene

Benzene forms a low-boiling azeotrope with water, removing water and leaving absolute ethanol.

19The dehydration of alcohols follows the order Tertiary > Secondary > Primary. This matches the stability order of:

A. Alkenes
B. Carbocations
C. Carbanions
D. Transition states

Answer: B. Carbocations

Dehydration proceeds via carbocation intermediates; stability of carbocation determines rate.

20Which compound will produce a yellow precipitate with NaOH and I₂ but will NOT react with Lucas reagent at room temperature?

A. Ethanol
B. 2-Propanol
C. 2-Methyl-2-propanol
D. Methanol

Answer: A. Ethanol

Ethanol gives iodoform test, but as a primary alcohol, it reacts slowly with Lucas reagent (no immediate turbidity).

21In the mechanism of acid-catalyzed hydration of ethene, the first step is:

A. Attack of nucleophile on alkene
B. Protonation of the alkene to form a carbocation
C. Attack of water on the alkene
D. Formation of an ester

Answer: B

Protonation of the double bond forms a carbocation, then water attacks.

22What is the product of the reaction between Phenol and Benzoyl Chloride in the presence of NaOH (Schotten-Baumann reaction)?

A. Phenyl benzoate
B. Benzyl phenoxide
C. Benzophenone
D. Phenyl benzyl ether

Answer: A. Phenyl benzoate

Phenol + benzoyl chloride → phenyl benzoate (ester).

23The reaction of 1,2-propanediol with Lead tetraacetate (Pb(OAc)₄) yields:

A. Acetaldehyde and Formaldehyde
B. Two moles of Acetaldehyde
C. Two moles of Formaldehyde
D. Propanal

Answer: A

Lead tetraacetate cleaves vicinal diols; 1,2-propanediol gives acetaldehyde and formaldehyde.

24When Phenol is treated with NaNO₂ and HCl at 0-5°C, followed by warming with water, the product is:

A. Benzene diazonium chloride
B. p-Nitrosophenol
C. Quinol
D. Catechol

Answer: B. p-Nitrosophenol

Phenol undergoes nitrosation at para position to give p-nitrosophenol.

25An alcohol C₄H₁₀O on treatment with CrO₃/H₂SO₄ gives a ketone. The alcohol is:

A. 1-Butanol
B. 2-Butanol
C. 2-Methyl-1-propanol
D. 2-Methyl-2-propanol

Answer: B. 2-Butanol

Secondary alcohol (2-butanol) gives ketone (butanone).

26The introduction of an electron-withdrawing group at the Meta position of phenol increases acidity:

A. More than at the Para position
B. Less than at the Para position
C. The same as at the Para position
D. Not at all

Answer: B

Para position allows direct resonance withdrawal, increasing acidity more than meta.

27Phenol is more reactive than Nitrobenzene towards Electrophilic Aromatic Substitution by a factor of approximately:

A. 10²
B. 10⁵
C. 10¹⁰
D. 10⁻⁵

Answer: C

Phenol is about 10¹⁰ times more reactive than nitrobenzene (strongly deactivated).

28In the Libermann's Nitroso test for phenols, the final deep blue/green color is due to the formation of:

A. Indophenol
B. Nitrosophenol
C. Picric acid
D. Quinone

Answer: A. Indophenol

The test involves formation of indophenol dye.

29Which of the following is an intermediate in the industrial synthesis of Phenol via the Cumene process?

A. Cumene hydroperoxide
B. Benzyl peroxide
C. Ethylbenzene
D. Phenyl acetate

Answer: A. Cumene hydroperoxide

Cumene (isopropylbenzene) is oxidized to cumene hydroperoxide, then cleaved to phenol and acetone.

30The reaction of phenol with FeCl₃ gives a violet complex. The formula of the complex is approximately:

A. [Fe(OC₆H₅)₆]³⁻
B. Fe(OC₆H₅)₃
C. [Fe(C₆H₅)₆]³⁺
D. Fe(C₆H₅)₃

Answer: A

The complex is hexaphenoxyferrate(III), [Fe(OPh)₆]³⁻.

31Coupling of Benzene diazonium chloride with phenol occurs at pH:

A. 2-3
B. 5-7
C. 9-10
D. 13-14

Answer: C. 9-10

Coupling requires slightly alkaline conditions to generate phenoxide ion (more reactive).

32Which of the following can be used to convert Phenol into p-Hydroxyacetophenone?

A. CH₃COCl / AlCl₃ (Fries Rearrangement)
B. CH₃I / AlCl₃
C. CH₃OH / H₂SO₄
D. CO₂ / NaOH

Answer: A

Phenyl acetate (from phenol + AcCl) undergoes Fries rearrangement to give ortho and para hydroxyacetophenones.

33Catalytic hydrogenation of Phenol using Pd/C at high pressure yields Cyclohexanol. If the reaction is stopped midway, we might isolate:

A. Cyclohexanone
B. Cyclohexene
C. Benzene
D. n-Hexanol

Answer: A. Cyclohexanone

Partial hydrogenation can give cyclohexanone as an intermediate.

34Which substituent decreases the acidity of phenol the most?

A. -OCH₃ (at Para)
B. -NO₂ (at Para)
C. -Cl (at Meta)
D. -CH₃ (at Meta)

Answer: A

Electron-donating group like -OCH₃ at para destabilizes phenoxide, decreasing acidity most.

35When Phenol is treated with excess of heavy water (D₂O) in the presence of a trace of acid, how many Hydrogen atoms are eventually replaced by Deuterium?

A. 1
B. 3
C. 4
D. 6

Answer: B. 3

The -OH hydrogen exchanges rapidly; also the ortho and para ring hydrogens exchange slowly under acidic conditions. Total up to 3 (OH + two ortho).

36An organic compound 'Z' (C₃H₈O₂) reacts with Sodium to evolve H₂ gas and forms a cyclic acetal with acetone. 'Z' is likely:

A. Propane-1,2-diol
B. Propane-1,3-diol
C. Methyl ethyl ether
D. Glycerol

Answer: A

1,2-diols form cyclic acetals with ketones. Propane-1,2-diol has two OH groups on adjacent carbons.

37Victor Meyer's test gives a 'Blood Red' color for which type of alcohol?

A. Primary
B. Secondary
C. Tertiary
D. Phenols

Answer: A. Primary

Victor Meyer test: primary alcohols give red color; secondary give blue; tertiary give no color.

38The product of the reaction between Phenol and Br₂ in Carbon Tetrachloride (CCl₄) is:

A. 2,4,6-Tribromophenol
B. o- and p-Bromophenol
C. m-Bromophenol
D. 2,4-Dibromophenol

Answer: B. o- and p-Bromophenol

In non-polar solvent, monobromination occurs (ortho and para).

39Which of the following is used as an 'Anti-freeze' in car radiators?

A. Methanol
B. Ethylene glycol
C. Diethyl ether
D. Phenol

Answer: B. Ethylene glycol

Ethylene glycol lowers freezing point of water.

40The conversion of 2-propanol to 1-propanol can be achieved by:

A. Dehydration followed by Hydroboration-Oxidation
B. Dehydration followed by Hydration
C. Oxidation followed by Reduction
D. Reaction with PCl₅ followed by H₂O

Answer: A

2-Propanol → propene (dehydration) → hydroboration-oxidation gives 1-propanol (anti-Markovnikov).

41Reduction of Acetone with LiAlH₄ yields:

A. 1-Propanol
B. 2-Propanol
C. Propane
D. Propanal

Answer: B. 2-Propanol

LiAlH₄ reduces ketones to secondary alcohols.

42Identify the correct statement regarding 'Power Alcohol':

A. It is 100% pure Ethanol
B. It is a mixture of 80% Petrol and 20% Ethanol
C. It is Ethanol used in generating electricity
D. It is Ethanol mixed with Methanol only

Answer: B

Power alcohol is a blend of petrol (80%) and ethanol (20%) used as fuel.

43Which reagent distinguishes between Benzyl alcohol and Phenol?

A. Na metal
B. NaHCO₃
C. FeCl₃
D. PCl₅

Answer: C. FeCl₃

Phenol gives violet color with FeCl₃; benzyl alcohol does not.

44Reaction of Phenol with Br₂ water gives a white ppt, but reaction with Br₂ in CS₂ at 0°C gives only monobromo products. This is because:

A. CS₂ is a polar solvent
B. H₂O facilitates the formation of phenoxide ion which is highly activating
C. Br₂ is more reactive in H₂O
D. CS₂ reacts with phenol

Answer: B

Water ionizes phenol slightly to phenoxide, which is extremely activating, leading to tribromo.

45What is the product of the reaction: Ethanol + CH₂N₂ (Diazomethane)?

A. Ethyl methyl ether
B. Diethyl ether
C. Propanol
D. Ethane

Answer: A. Ethyl methyl ether

Diazomethane methylates alcohols to methyl ethers.

46The major product formed when 1-ethoxy-2-methylpropane reacts with one equivalent of HI is:

A. Ethyl iodide and Isobutyl alcohol
B. Ethanol and Isobutyl iodide
C. Ethyl iodide and Isopropyl alcohol
D. Iodoethane and tert-butyl alcohol

Answer: B

HI cleaves ethers; the larger alkyl group becomes iodide (SN2), so isobutyl iodide and ethanol.

47The reaction of Phenol with Na₂Cr₂O₇ / H₂SO₄ gives a conjugate diketone. This product is:

A. p-Benzoquinone
B. o-Benzoquinone
C. Hydroquinone
D. Phthalic acid

Answer: A. p-Benzoquinone

Oxidation of phenol gives p-benzoquinone.

48Acidity of Alcohols in the gas phase follows the order:

A. Primary > Secondary > Tertiary
B. Tertiary > Secondary > Primary
C. Secondary > Primary > Tertiary
D. All are equally acidic

Answer: B

In gas phase (no solvation), tertiary alcohols are more acidic due to inductive stabilization of alkoxide by alkyl groups.

49Reaction of 3-methyl-2-butanol with HCl gives 2-chloro-2-methylbutane as the major product. This is an example of:

A. SN2 reaction
B. Carbocation rearrangement
C. Elimination
D. Free radical substitution

Answer: B. Carbocation rearrangement

A hydride or methyl shift occurs to form a more stable tertiary carbocation.

50Phenolphthalein is prepared by heating Phenol with Phthalic anhydride in the presence of:

A. NaOH
B. Conc. H₂SO₄
C. AlCl₃
D. FeCl₃

Answer: B. Conc. H₂SO₄

Phenol + phthalic anhydride + conc. H₂SO₄ gives phenolphthalein.

📄Past Paper MCQs

📅 Actual MDCAT / NUMS Questions

50 MCQs

1Which of the following represents a 'secondary' alcohol?

MDCAT 2019

A. 2-Methyl-2-propanol
B. 2-Methyl-1-propanol
C. 2-Butanol
D. 1-Butanol

Answer: C. 2-Butanol

2-Butanol has OH on C2, which is attached to two other carbons → secondary.

2The IUPAC name of the compound (CH₃)₂CH-CH₂-OH is:

UHS 2017

A. 2-Methyl-1-propanol
B. Isobutyl alcohol
C. 1-Butanol
D. 2-Butanol

Answer: A

Longest chain is three carbons (propane) with a methyl on C2 → 2-methylpropan-1-ol.

3Alcohols have higher boiling points than alkanes of similar molecular mass because of:

NUMS 2021

A. Ionic bonding
B. London dispersion forces
C. Intermolecular hydrogen bonding
D. Intramolecular hydrogen bonding

Answer: C

Hydrogen bonding between alcohol molecules raises boiling point.

4The C-O-H bond angle in alcohols is approximately:

MDCAT 2020

A. 109.5°
B. 120°
C. 105°
D. 180°

Answer: A

Actually about 108.5°, but closest is 109.5° (tetrahedral).

5Which of the following is a trihydric alcohol?

UHS 2016

A. Ethylene glycol
B. Glycerol
C. Phenol
D. Ethanol

Answer: B. Glycerol

Glycerol has three -OH groups.

6The solubility of alcohols in water decreases as:

NUMS 2020

A. The length of the alkyl chain increases
B. The number of -OH groups increases
C. The temperature decreases
D. Pressure increases

Answer: A

Longer alkyl chain increases hydrophobicity.

7Methylated spirit contains 10% of which substance to make it unfit for drinking?

MDCAT 2018

A. Pyridine
B. Acetone
C. Methanol
D. Benzene

Answer: A. Pyridine

Methylated spirit contains methanol and pyridine (or other denaturants).

8Which of the following isomers of C₄H₁₀O is optically active?

UHS 2019

A. 1-Butanol
B. 2-Butanol
C. 2-Methyl-1-propanol
D. 2-Methyl-2-propanol

Answer: B. 2-Butanol

2-Butanol has a chiral carbon.

9Which of the following is also known as 'Wood Spirit'?

NUMS 2018

A. Ethanol
B. Methanol
C. Phenol
D. Ethylene glycol

Answer: B. Methanol

Methanol from wood distillation.

10In the structure of phenol, the carbon atom attached to the hydroxyl group is:

MDCAT 2022

A. sp hybridized
B. sp² hybridized
C. sp³ hybridized
D. dsp² hybridized

Answer: B. sp² hybridized

Benzene ring carbons are sp².

11Lucas reagent is a mixture of:

UHS 2015

A. HCl and CuCl₂
B. HCl and anhydrous ZnCl₂
C. H₂SO₄ and ZnCl₂
D. HCl and FeCl₃

Answer: B

Conc. HCl + anhydrous ZnCl₂.

12Which alcohol reacts immediately with Lucas reagent to form an oily layer of alkyl halide?

NUMS 2021

A. Methanol
B. Ethanol
C. 2-Propanol
D. 2-Methyl-2-propanol

Answer: D

Tertiary alcohol gives immediate turbidity.

13The Iodoform test is used to distinguish between:

MDCAT 2017

A. Methanol and Ethanol
B. Ethanol and Propan-2-ol
C. Phenol and Ethanol
D. Propan-1-ol and Propan-2-ol

Answer: A

Ethanol gives iodoform, methanol does not.

14When ethanol is heated with concentrated H₂SO₄ at 170°C, the major product is:

UHS 2016

A. Diethyl ether
B. Ethene
C. Ethyl hydrogen sulfate
D. Ethane

Answer: B. Ethene

Intramolecular dehydration gives ethene.

15Primary alcohols on oxidation with acidified K₂Cr₂O₇ primarily give:

NUMS 2019

A. Ketones
B. Aldehydes
C. Ethers
D. Alkanes

Answer: B. Aldehydes

Aldehydes (but can further oxidize to acids).

16Secondary alcohols on oxidation with Na₂Cr₂O₇ / H₂SO₄ produce:

MDCAT 2021

A. Aldehydes
B. Carboxylic acids
C. Ketones
D. Esters

Answer: C. Ketones

Ketones.

17Which of the following reagents can convert an alcohol into an alkyl chloride with SO₂ and HCl as gaseous byproducts?

UHS 2018

A. PCl₅
B. PCl₃
C. SOCl₂
D. HCl/ZnCl₂

Answer: C. SOCl₂

Thionyl chloride.

18The reaction between an alcohol and a carboxylic acid to form an ester is an example of:

NUMS 2020

A. Dehydrogenation
B. Nucleophilic substitution
C. Electrophilic addition
D. Elimination

Answer: B

Esterification is nucleophilic acyl substitution.

19During esterification, which bond of the alcohol is broken?

MDCAT 2022

A. C-O bond
B. O-H bond
C. C-C bond
D. C-H bond

Answer: B. O-H bond

The O-H bond breaks; the H combines with OH from acid to form water.

20In the reaction of alcohols with Sodium metal, which gas is evolved?

UHS 2014

A. Oxygen
B. Carbon dioxide
C. Hydrogen
D. Methane

Answer: C. Hydrogen

Hydrogen gas.

21The order of reactivity of alcohols when the C-O bond breaks is:

NUMS 2022

A. Primary > Secondary > Tertiary
B. Tertiary > Secondary > Primary
C. Secondary > Primary > Tertiary
D. All react equally

Answer: B

Tertiary most reactive in SN1.

22Dehydrogenation of a secondary alcohol over heated Copper at 300°C yields:

MDCAT 2023

A. Aldehyde
B. Ketone
C. Alkene
D. Alkane

Answer: B. Ketone

Secondary alcohols give ketones.

23Tertiary alcohols are resistant to oxidation because:

UHS 2015

A. They are very stable
B. They lack an α-hydrogen
C. They have a high boiling point
D. They are more acidic

Answer: B. They lack an α-hydrogen

No hydrogen on carbinol carbon.

24When ethanol is treated with excess H₂SO₄ at 140°C, the product is:

NUMS 2018

A. Ethene
B. Diethyl ether
C. Ethyl hydrogen sulfate
D. Ethyne

Answer: B. Diethyl ether

Intermolecular dehydration gives ether.

25Which alcohol will give a yellow precipitate of CHI₃ with I₂/NaOH?

MDCAT 2020

A. Methanol
B. 1-Propanol
C. 2-Propanol
D. 1-Butanol

Answer: C. 2-Propanol

2-Propanol (isopropyl alcohol) has CH₃CH(OH)- group.

26Phenol is also known as:

UHS 2017

A. Carboxylic acid
B. Carbolic acid
C. Carbonic acid
D. Oxalic acid

Answer: B. Carbolic acid

Phenol = carbolic acid.

27Phenol is more acidic than ethanol because:

NUMS 2019

A. Ethoxide ion is more stable than phenoxide ion
B. Phenoxide ion is resonance stabilized
C. Phenol has a higher molecular mass
D. Ethanol is a liquid

Answer: B

Phenoxide resonance stabilization.

28Which of the following has the highest acidity?

MDCAT 2021

A. Ethanol
B. Water
C. Phenol
D. Methanol

Answer: C. Phenol

Phenol (pKa ~10) > water (15.7) > alcohols (16).

29Phenol reacts with Bromine water to give a white precipitate of:

UHS 2016

A. 2-Bromophenol
B. 4-Bromophenol
C. 2,4,6-Tribromophenol
D. Bromobenzene

Answer: C

Tribromophenol.

30Nitration of phenol with dilute HNO₃ at 25°C yields a mixture of:

NUMS 2020

A. Ortho and Para nitrophenol
B. Meta nitrophenol
C. Picric acid
D. Nitrobenzene

Answer: A

Ortho and para.

31Picric acid is chemically:

MDCAT 2018

A. 2,4,6-Tribromophenol
B. 2,4,6-Trinitrophenol
C. 1,3,5-Trinitrophenol
D. Trinitrotoluene

Answer: B. 2,4,6-Trinitrophenol

Picric acid = 2,4,6-trinitrophenol.

32Phenol reacts with Zn dust on heating to produce:

UHS 2019

A. Cyclohexane
B. Benzene
C. Zinc phenoxide
D. Benzaldehyde

Answer: B. Benzene

Benzene.

33The reaction of Phenol with NaOH and CO₂ at 140°C to form Salicylic acid is called:

NUMS 2021

A. Reimer-Tiemann reaction
B. Kolbe's reaction
C. Cannizzaro reaction
D. Wurtz reaction

Answer: B. Kolbe's reaction

Kolbe-Schmitt reaction.

34Phenol gives a characteristic violet color with:

MDCAT 2022

A. Bromine water
B. Neutral FeCl₃
C. Lucas reagent
D. NaOH

Answer: B. Neutral FeCl₃

FeCl₃ test for phenols.

35Bakelite is a polymer formed by the reaction of Phenol with:

UHS 2015

A. Acetaldehyde
B. Formaldehyde
C. Acetone
D. Ethylene glycol

Answer: B. Formaldehyde

Phenol + formaldehyde.

36When phenol is treated with Br₂ in CS₂ at low temperature, the major product is:

NUMS 2022

A. 2,4,6-Tribromophenol
B. p-Bromophenol
C. m-Bromophenol
D. Bromobenzene

Answer: B. p-Bromophenol

Monobromination (para).

37The presence of an electron-withdrawing group (like -NO₂) on the phenol ring:

MDCAT 2023

A. Decreases acidity
B. Increases acidity
C. Has no effect on acidity
D. Makes it basic

Answer: B. Increases acidity

Increases acidity.

38Reimer-Tiemann reaction of Phenol with CHCl₃/KOH yields:

UHS 2018

A. Salicylic acid
B. Salicylaldehyde
C. Picric acid
D. Benzyl alcohol

Answer: B. Salicylaldehyde

Salicylaldehyde (ortho-formyl).

39Phenol is less acidic than:

NUMS 2019

A. Ethanol
B. Water
C. Carboxylic acids
D. Alcohols

Answer: C. Carboxylic acids

Carboxylic acids are stronger (pKa ~4-5).

40Hydrogenation of phenol in the presence of Nickel catalyst at 150°C yields:

MDCAT 2020

A. Benzene
B. n-Hexane
C. Cyclohexanol
D. Cyclohexane

Answer: C. Cyclohexanol

Cyclohexanol.

41Which test is used to distinguish between Phenol and Ethanol?

UHS 2017

A. Sodium test
B. Lucas test
C. FeCl₃ test
D. Esterification test

Answer: C. FeCl₃ test

FeCl₃ test.

42Methanol is industrially prepared from 'Synthesis Gas' which is a mixture of:

NUMS 2021

A. CO + H₂
B. CO₂ + H₂
C. CH₄ + H₂O
D. CO + N₂

Answer: A. CO + H₂

CO + H₂ (water gas shift).

43The enzyme used in the fermentation of molasses to convert Glucose into Ethanol is:

MDCAT 2016

A. Diastase
B. Maltase
C. Zymase
D. Invertase

Answer: C. Zymase

Zymase from yeast.

44Which of the following will not react with NaOH?

UHS 2019

A. Phenol
B. Ethanol
C. Acetic acid
D. Picric acid

Answer: B. Ethanol

Ethanol does not react with NaOH.

45Ethers are functional group isomers of:

NUMS 2020

A. Ketones
B. Alcohols
C. Aldehydes
D. Esters

Answer: B. Alcohols

Same formula as alcohols.

46In the Williamson Synthesis of ethers, which mechanism is followed?

MDCAT 2022

A. SN1
B. SN2
C. E1
D. E2

Answer: B. SN2

SN2 (alkoxide + alkyl halide).

47The compound used as an antifreeze in automobile radiators is:

UHS 2015

A. Methanol
B. Ethanol
C. Ethylene glycol
D. Glycerol

Answer: C. Ethylene glycol

Ethylene glycol.

48Which of the following is most reactive towards Electrophilic Aromatic Substitution?

NUMS 2021

A. Benzene
B. Nitrobenzene
C. Phenol
D. Chlorobenzene

Answer: C. Phenol

Phenol is highly activated.

49Rectified spirit contains how much percent of Ethanol?

MDCAT 2018

A. 100%
B. 95%
C. 50%
D. 5%

Answer: B. 95%

95% ethanol, 5% water.

50Phenoxide ion is more stable than phenol because of:

UHS 2020

A. Absence of charge separation in resonance
B. Presence of charge separation in resonance
C. Inductive effect
D. Steric hindrance

Answer: A

In phenoxide, resonance structures have negative charge on oxygen without charge separation.

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❔Frequently Asked Questions

What is the difference between an alcohol and a phenol?

Why is phenol more acidic than ethanol?

How does the Lucas test distinguish primary, secondary, and tertiary alcohols?

What is the FeCl₃ test used for?

What are the products of oxidation of primary, secondary, and tertiary alcohols?

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What is the acidity order of phenol, water, and ethanol?

The acidity order is phenol (pKa ≈ 10) > water (pKa ≈ 15.7) > ethanol (pKa ≈ 16). Phenol is the strongest acid because its conjugate base is resonance-stabilised.

What are the key differences between alcohols and phenols in their reactions with NaOH and Na metal?

What is esterification?

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How many MCQs come from Alcohols and Phenols in MDCAT?

Alcohols and Phenols typically contribute 2–3 MCQs in MDCAT Chemistry. The chapter is high-yield because questions on acidity, Lucas test, and phenol reactivity are frequently repeated.

What is the product of phenol with Zn dust?

Phenol + Zn dust on heating gives benzene (C₆H₆). This is a reduction reaction where Zn removes the oxygen.

What is the Kolbe-Schmitt reaction?

Sodium phenoxide + CO₂ (under pressure, 125°C) → sodium salicylate → acidification → salicylic acid. Salicylic acid is used to make aspirin.

What is the Reimer-Tiemann reaction?

Phenol + CHCl₃ + KOH → salicylaldehyde (ortho-hydroxybenzaldehyde). The electrophile is dichlorocarbene (:CCl₂).

What are the differences between 1°, 2°, and 3° alcohols?

1°: –OH carbon attached to 1 alkyl group. 2°: attached to 2 alkyl groups. 3°: attached to 3 alkyl groups. Reactivity in SN1 follows 3° > 2° > 1°.

Alcohols & Phenols — Nomenclature, Reactivity & Tests

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❓People Also Ask — Alcohols & Phenols

📋Syllabus & Learning Outcomes

📝Full Notes — Alcohols & Phenols

1. Alcohols — Nomenclature & Structure

2. Reactivity of Alcohols

3. Ethers & Esters from Alcohols

4. Phenols — Nomenclature, Structure & Reactivity

5. Electrophilic Aromatic Substitution in Phenol

6. Distinction: Alcohol vs Phenol

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