Electrochemistry MDCAT Notes, MCQs, Past Papers & Answers – Redox, Oxidation Numbers, SHE, Electrode Potential

Q: What is a redox reaction?

A redox reaction is a chemical reaction in which oxidation and reduction occur simultaneously. One species loses electrons (is oxidised) while another gains electrons (is reduced).

Q: How is oxidation defined in terms of oxidation number?

Oxidation is an increase in oxidation number. Reduction is a decrease in oxidation number.

Q: What is the difference between an oxidising agent and a reducing agent?

An oxidising agent gains electrons and is itself reduced (its oxidation number decreases). A reducing agent loses electrons and is itself oxidised (its oxidation number increases).

Q: What is the cathode and anode in an electrochemical cell?

Cathode is the electrode where reduction occurs. Anode is the electrode where oxidation occurs. In a galvanic cell, cathode is positive and anode is negative; in an electrolytic cell, cathode is negative and anode is positive.

Q: What is electrode potential?

Electrode potential is the potential difference developed between an electrode and its ion solution. It measures the tendency of the electrode to gain or lose electrons.

Q: What is the Standard Hydrogen Electrode (SHE)?

SHE is the reference electrode used to measure standard electrode potentials. It consists of a platinum electrode in 1 M H+ solution with H2 gas at 1 atm and 25°C. Its potential is defined as 0.00 V.

Q: What is standard electrode potential?

Standard electrode potential (E°) is the potential of an electrode measured against SHE under standard conditions (1 M concentration, 1 atm pressure, 25°C).

Q: What does a positive E° mean?

A positive E° means the electrode has a greater tendency to be reduced than H+; it is a stronger oxidising agent. A negative E° means it is a stronger reducing agent.

Q: How is cell potential calculated?

E°cell = E°cathode − E°anode (using reduction potentials). For a spontaneous reaction, E°cell must be positive.

⚡ Chapter · MDCAT Chemistry

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

Electrochemistry — Complete MDCAT Notes & MCQs

Full MDCAT Chemistry notes on electrochemistry: redox reactions, oxidation numbers, identifying oxidation/reduction, cathode and anode, electrode potential, Standard Hydrogen Electrode (SHE), and standard electrode potentials. Includes 200 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 Electrochemistry.

What is a redox reaction?

Redox reaction is a chemical reaction in which oxidation and reduction occur simultaneously. One species loses electrons (oxidised) while another gains electrons (reduced).

Oxidation vs reduction?

Oxidation = increase in oxidation number (loss of electrons). Reduction = decrease in oxidation number (gain of electrons). OIL RIG.

Oxidising vs reducing agent?

Oxidising agent gains electrons and is itself reduced. Reducing agent loses electrons and is itself oxidised.

Rules for oxidation numbers?

Free element = 0; monatomic ion = charge; O = −2 (except peroxides −1, OF₂ +2); H = +1 (except hydrides −1); sum in neutral compound = 0, in polyatomic ion = charge.

Cathode vs anode?

Cathode = reduction occurs. Anode = oxidation occurs. Galvanic: cathode positive, anode negative. Electrolytic: cathode negative, anode positive.

What is electrode potential?

Electrode potential is the potential difference between an electrode and its ion solution, measuring tendency to gain or lose electrons (in volts).

What is Standard Hydrogen Electrode?

SHE is a reference electrode with Pt in 1 M H⁺, H₂ at 1 atm, 25°C. Its potential is defined as 0.00 V.

Standard electrode potential?

E° is the potential of an electrode measured against SHE under standard conditions (1 M, 1 atm, 25°C). Positive E° = stronger oxidising agent.

What is the electrochemical series?

The electrochemical series arranges elements by standard reduction potentials. More negative E° = stronger reducing agent; more positive = stronger oxidising agent.

Cell potential formula?

E°cell = E°cathode − E°anode. For a spontaneous reaction, E°cell must be positive.

What is disproportionation?

Disproportionation is a redox reaction in which the same element is both oxidised and reduced (e.g., Cl₂ + 2OH⁻ → Cl⁻ + ClO⁻ + H₂O).

What is the Nernst equation?

E = E° − (RT/nF) ln Q. At 25°C: E = E° − (0.059/n) log Q. Relates cell potential to concentration.

What is a salt bridge?

A salt bridge maintains electrical neutrality by allowing ions to migrate between half-cells, completing the circuit.

What is a galvanic cell?

A galvanic (voltaic) cell converts chemical energy into electrical energy via a spontaneous redox reaction. Anode = negative, cathode = positive.

How many MCQs from Electrochemistry?

Electrochemistry typically contributes 3–5 MCQs out of 81 Chemistry MCQs in MDCAT.

❓People Also Ask — Electrochemistry

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

QWhat is the difference between oxidation number and valency?

Oxidation number is the formal charge assigned to an atom assuming complete electron transfer, whereas valency is the combining capacity of an element (number of bonds it can form). Oxidation number can be fractional, zero, or negative.

QWhy is the electrode potential of SHE exactly zero?

The absolute potential of a single electrode cannot be measured. SHE is chosen as a reference by convention with potential 0.00 V, so all other electrode potentials are measured relative to it.

QWhy is platinum used in SHE?

Platinum is inert (does not react) and provides a surface for the electron transfer between H₂ gas and H⁺ ions. It is coated with platinum black to increase surface area for adsorption.

QWhat does a positive standard reduction potential mean?

A positive E° means the electrode has a greater tendency to gain electrons (be reduced) than H⁺. This makes it a stronger oxidising agent.

QWhat is the difference between a galvanic and an electrolytic cell?

Galvanic cell: spontaneous redox reaction produces electrical energy; anode is negative, cathode positive. Electrolytic cell: electrical energy drives a non-spontaneous reaction; anode is positive, cathode negative.

QHow do you balance a redox reaction in acidic medium?

Split into half-reactions. Balance all atoms except H and O. Add H₂O to balance O. Add H⁺ to balance H. Balance charge by adding electrons. Multiply to equalise electrons, then add half-reactions and cancel.

QWhat is the electrochemical series?

The electrochemical series arranges elements by standard reduction potentials. Elements with more negative E° (e.g., Li, K, Ca) are stronger reducing agents; those with positive E° (e.g., Cu, Ag, Au) are stronger oxidising agents.

QHow do you determine the strongest oxidising agent?

The species with the most positive standard reduction potential (e.g., F₂, E° = +2.87 V) is the strongest oxidising agent, as it is most easily reduced.

QWhat are the products of the reaction between Cl₂ and hot NaOH?

Hot concentrated NaOH: 3Cl₂ + 6NaOH → 5NaCl + NaClO₃ + 3H₂O. The products are chloride and chlorate(V). In cold dilute NaOH, the products are chloride and chlorate(I).

QWhat is the oxidation number of Mn in KMnO₄?

In KMnO₄, K = +1, each O = −2. So Mn + 1 + 4(−2) = 0 → Mn = +7.

QWhat is the oxidation number of Cr in K₂Cr₂O₇?

K₂Cr₂O₇: 2(+1) + 2x + 7(−2) = 0 → 2 + 2x − 14 = 0 → x = +6.

QWhy is Li the strongest reducing agent even though Cs is more reactive?

In aqueous solution, Li has the most negative standard reduction potential due to very high hydration energy of the small Li⁺ ion, making Li → Li⁺(aq) highly favourable. In the gas phase, Cs would be stronger, but in solution Li is stronger.

QWhat is the salt bridge made of?

A salt bridge is usually a glass tube containing a gel (e.g., agar) soaked in an inert electrolyte such as KCl or KNO₃. It allows ions to flow between half-cells without mixing the solutions.

QWhat happens if E°cell is negative?

A negative E°cell means the reaction is non-spontaneous under standard conditions. The reverse reaction would be spontaneous. This also corresponds to K < 1.

QWhat is the relation between ΔG° and E°cell?

ΔG° = −nFE°cell. A positive E°cell gives a negative ΔG°, meaning the reaction is spontaneous (products favoured).

QWhat is the difference between oxidation potential and reduction potential?

Oxidation potential is the tendency to lose electrons (be oxidised). Reduction potential is the tendency to gain electrons (be reduced). They have the same magnitude but opposite signs.

QWhat is a fuel cell?

A fuel cell is an electrochemical cell that converts chemical energy of fuel (e.g., H₂, CH₃OH) and oxidant (O₂) into electricity continuously. The H₂-O₂ fuel cell produces only water as a by-product.

QWhy does SHE need H₂ at 1 atm and 1 M H⁺?

Standard conditions (1 M, 1 atm, 25°C) are needed so that the standard electrode potential is reproducible and comparable across different electrodes.

QWhy is the oxidation state of F always −1?

Fluorine is the most electronegative element, so it always gains electrons in compounds — its oxidation state is always −1 (except F₂ where it is 0).

QWhat is the strongest oxidising agent and why?

F₂ is the strongest oxidising agent because F has the most positive reduction potential (+2.87 V), highest electronegativity, and lowest bond dissociation energy, giving it a great tendency to gain electrons.

📋Syllabus & Learning Outcomes

According to PMDC/PMC MDCAT syllabus, Electrochemistry covers:

1 Give the characteristics of a redox reaction.
2 Define oxidation and reduction in terms of a change in oxidation number.
3 Use the oxidation number change method to identify atoms being oxidized or reduced in redox reactions.
4 Define cathode, anode, electrode potential, and Standard Hydrogen Electrode (SHE).
5 Define the standard electrode potential of an electrode.

📝Full Notes — Electrochemistry

⚡ Electrochemistry – Schematic Notes

🔄 1. Characteristics of Redox Reactions

Redox reaction: Oxidation and reduction occur simultaneously.
Oxidation involves loss of electrons; reduction involves gain of electrons (OIL RIG).
One species is oxidised (reducing agent) and another is reduced (oxidising agent).
Total increase in oxidation number = total decrease in oxidation number.
Often accompanied by observable changes: colour change, gas evolution, precipitation, or current flow in electrochemical cells.

🔢 2. Oxidation Number – Definition of Oxidation & Reduction

Oxidation: Increase in oxidation number (e.g., Zn⁰ → Zn²⁺, oxidation number increases from 0 to +2).
Reduction: Decrease in oxidation number (e.g., Cu²⁺ → Cu⁰, oxidation number decreases from +2 to 0).
Oxidising agent: Species that gains electrons and is itself reduced (oxidation number decreases).
Reducing agent: Species that loses electrons and is itself oxidised (oxidation number increases).

📏 Oxidation Number Rules (Key)

Free element: 0 (e.g., O₂, Zn, Cl₂).
Monatomic ion: equals its charge (e.g., Na⁺ = +1, Cl⁻ = −1).
Oxygen: −2 (except peroxides: −1; OF₂: +2).
Hydrogen: +1 (except metal hydrides: −1, e.g., NaH).
Sum of oxidation numbers in a neutral compound = 0; in a polyatomic ion = charge on the ion.

🧮 3. Identifying Oxidation & Reduction

Assign oxidation numbers to all atoms in reactants and products.
Identify which atom's oxidation number increases (oxidised) and which decreases (reduced).
Example: Zn + CuSO₄ → ZnSO₄ + Cu
- Zn: 0 → +2 (oxidation number increases, Zn is oxidised – reducing agent).
- Cu: +2 → 0 (oxidation number decreases, Cu²⁺ is reduced – oxidising agent).
For balancing redox equations: split into half‑reactions, balance atoms (except H, O), balance O with H₂O, balance H with H⁺ (acidic medium) or OH⁻ (basic medium), balance charge with electrons, then combine.

🔌 4. Electrochemical Terms

Cathode: Electrode where reduction occurs (gains electrons). In electrolytic cell: negative; in galvanic cell: positive.
Anode: Electrode where oxidation occurs (loses electrons). In electrolytic cell: positive; in galvanic cell: negative.
Electrode potential: Tendency of an electrode to gain or lose electrons when in contact with its ion solution; measured in volts (V).
Standard Hydrogen Electrode (SHE): Reference electrode with assigned potential of 0.00 V at all temperatures.
- Construction: Platinum electrode in 1 M H⁺ solution, H₂ gas bubbled at 1 atm, 25°C.
- Half‑reaction: 2H⁺(aq) + 2e⁻ ⇌ H₂(g), E° = 0.00 V.
- Used to measure standard electrode potentials of other electrodes by coupling with them.

⚡ 5. Standard Electrode Potential (E°)

Definition: The potential of an electrode measured relative to SHE under standard conditions (1 M ion concentration, 1 atm gas pressure, 25°C).
Positive E°: electrode has greater tendency to be reduced (stronger oxidising agent) than H⁺. e.g., Cu²⁺/Cu = +0.34 V.
Negative E°: electrode has less tendency to be reduced (stronger reducing agent) than H⁺. e.g., Zn²⁺/Zn = −0.76 V.
For galvanic cell: E°_cell = E°_cathode − E°_anode = E°_reduction(cathode) − E°_reduction(anode).
Larger (more positive) E° → greater oxidising power. Smaller (more negative) E° → greater reducing power.
Standard conditions are essential; E varies with concentration (Nernst equation: E = E° − (RT/nF)lnQ).

⚡ Cations/Potentials comparison (Positive E°):

The more positive the standard reduction potential, the stronger the oxidising agent (e.g., F₂/F⁻ = +2.87 V, strongest oxidising agent).
The more negative the standard reduction potential, the stronger the reducing agent (e.g., Li⁺/Li = −3.05 V, strongest reducing agent).

🔑 High‑Yield MCQs & Traps

Oxidation = loss of electrons = increase in oxidation number; Reduction = gain = decrease.
Oxidising agent is itself reduced; reducing agent is itself oxidised.
Oxidation numbers: free element = 0, O = −2 (except peroxides), H = +1 (except hydrides).
Anode = oxidation (both cells); cathode = reduction (both cells). Galvanic: anode (−), cathode (+); Electrolytic: anode (+), cathode (−).
SHE has E° = 0.00 V; used as reference.
More positive E° = greater tendency to be reduced (better oxidising agent).
E°_cell = E°_cathode − E°_anode (for spontaneous cell, E°_cell must be positive).
Standard conditions: 1 M, 1 atm, 25°C.
⚠️ Traps: “Anode is always positive” → False (only in electrolytic cell). “E° values change with stoichiometric coefficients” → False (intensive property). “Oxidation occurs at the cathode” → False (reduction). “Reducing agent has high positive E°” → False (negative E° = strong reducing agent).

💡 MDCAT focus: Oxidation numbers, identifying redox changes, SHE, and standard electrode potentials.

✅Practice MCQs — Test 1

🧪 Basic Concepts

50 MCQs

1A chemical reaction in which both oxidation and reduction take place simultaneously is known as:

A. Hydrolysis
B. Redox reaction
C. Isomerization
D. Neutralization

Answer: B

Redox reactions involve simultaneous oxidation and reduction.

2In terms of oxidation number, 'Oxidation' is defined as:

A. Decrease in oxidation number
B. Increase in oxidation number
C. No change in oxidation number
D. Gain of electrons

Answer: B

Oxidation is increase in oxidation number (loss of electrons).

3In the reaction Zn + Cu²⁺ → Zn²⁺ + Cu, which species is being reduced?

A. Zn
B. Cu²⁺
C. Zn²⁺
D. Cu

Answer: B

Cu²⁺ gains electrons (reduction) to become Cu.

4The oxidation number of an element in its free (uncombined) state, such as H₂ or S₈, is always:

A. +1
B. -1
C. 0
D. Dependent on the group number

Answer: C

Free elements have oxidation number 0.

5In almost all its compounds, the oxidation number of Oxygen is -2, EXCEPT in peroxides where it is:

A. -1
B. +2
C. +1
D. -1/2

Answer: A

In peroxides (e.g., H₂O₂), oxygen has oxidation state -1.

6What is the oxidation number of Chromium in K₂Cr₂O₇?

A. +3
B. +5
C. +6
D. +7

Answer: C. +6

K₂Cr₂O₇: 2(+1) + 2x + 7(-2)=0 → 2+2x-14=0 → 2x=12 → x=+6.

7In the compound OF₂, the oxidation state of Oxygen is:

A. -2
B. -1
C. +2
D. +1

Answer: C. +2

F is more electronegative, so F=-1, O=+2.

8The sum of oxidation numbers of all atoms in a neutral molecule is:

A. Equal to the charge of the ion
B. Always +1
C. Always 0
D. Always -1

Answer: C

For a neutral molecule, sum of oxidation numbers = 0.

9When an atom undergoes reduction, it acts as a/an:

A. Oxidizing agent
B. Reducing agent
C. Catalyst
D. Solvent

Answer: A

Reduction of an atom means it gains electrons, so it oxidizes another species → it is an oxidizing agent.

10In the reaction 2Na + Cl₂ → 2NaCl, Chlorine is the:

A. Reducing agent
B. Oxidizing agent
C. Species being oxidized
D. Catalyst

Answer: B

Cl₂ gains electrons (reduced), so it is the oxidizing agent.

11In the reaction MnO₂ + 4HCl → MnCl₂ + Cl₂ + 2H₂O, which atom is oxidized?

A. Mn
B. O
C. H
D. Cl

Answer: D

Cl in HCl (-1) changes to Cl₂ (0), so Cl is oxidized.

12When KMnO₄ acts as an oxidizing agent in an acidic medium, the oxidation number of Mn changes from +7 to:

A. +4
B. +6
C. +2
D. 0

Answer: C. +2

In acidic medium, MnO₄⁻ reduces to Mn²⁺ (oxidation state +2).

13In the oxidation number change method of balancing, the first step is usually to:

A. Balance O and H
B. Assign oxidation numbers to all atoms
C. Multiply by a coefficient
D. Add water molecules

Answer: B

First assign oxidation numbers to identify which atoms change.

14If an element's oxidation number changes from +5 to +2, the element has:

A. Lost 3 electrons
B. Gained 3 electrons
C. Lost 2 electrons
D. Gained 5 electrons

Answer: B

Decrease in oxidation number means gain of electrons (3 electrons).

15In the reaction H₂S + Cl₂ → 2HCl + S, the reducing agent is:

A. Cl₂
B. S
C. H₂S
D. HCl

Answer: C

S in H₂S (-2) changes to S(0), so H₂S is oxidized and is the reducing agent.

16Which of the following is NOT a redox reaction?

A. AgNO₃ + NaCl → AgCl + NaNO₃
B. 2H₂ + O₂ → 2H₂O
C. Mg + 2HCl → MgCl₂ + H₂
D. Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag

Answer: A

Double displacement with no change in oxidation numbers.

17The oxidation number of Phosphorus in HPO₄²⁻ is:

A. +3
B. +5
C. +4
D. +6

Answer: B. +5

HPO₄²⁻: H=+1, O=-2, total charge -2: +1 + P + 4(-2) = -2 → P -7 = -2 → P=+5.

18In the reaction Sn²⁺ + 2Fe³⁺ → Sn⁴⁺ + 2Fe²⁺, the species being oxidized is:

A. Fe³⁺
B. Fe²⁺
C. Sn²⁺
D. Sn⁴⁺

Answer: C

Sn²⁺ loses electrons to become Sn⁴⁺, so it is oxidized.

19Which element typically exhibits an oxidation state of +1 in its compounds?

A. Magnesium
B. Aluminium
C. Sodium
D. Oxygen

Answer: C

Group 1 metals (alkali metals) have +1 oxidation state.

20The oxidation number of S in Na₂S₂O₃ (Sodium Thiosulphate) is:

A. +2
B. +4
C. +6
D. 0

Answer: A. +2

Average oxidation state: 2(+1) + 2x + 3(-2)=0 → 2+2x-6=0 → 2x=4 → x=+2.

21In an electrochemical cell, the electrode where oxidation occurs is the:

A. Cathode
B. Anode
C. Salt bridge
D. Reference electrode

Answer: B

Anode is where oxidation occurs.

22In a galvanic (voltaic) cell, the cathode is the:

A. Negative electrode
B. Positive electrode
C. Site of electron loss
D. Site of oxidation

Answer: B

In a galvanic cell, cathode is positive (reduction occurs).

23The potential difference established between an electrode and its own ions in solution is called:

A. Cell potential
B. Ionization potential
C. Electrode potential
D. Electromotive force

Answer: C

Electrode potential is the potential of a single electrode.

24The absolute value of a single electrode potential:

A. Can be measured using a voltmeter directly
B. Cannot be measured directly
C. Is always zero
D. Is equal to the SHE potential

Answer: B

Only differences can be measured; absolute values cannot.

25In an electrolytic cell, the cathode is assigned a _____ charge.

A. Positive
B. Negative
C. Neutral
D. Oscillating

Answer: B

In electrolytic cell, cathode is negative (attracts cations).

26Reduction always takes place at the:

A. Anode
B. Cathode
C. Salt bridge
D. Interface of the two containers

Answer: B

Cathode is the site of reduction.

27The function of an electrode in a cell is to:

A. Provide a surface for electron transfer
B. Act as a bridge for ions
C. Dissolve into the solution only
D. Stop the reaction

Answer: A

Electrodes allow electron transfer between the cell and external circuit.

28An inert electrode used in many gas electrodes like SHE is made of:

A. Copper
B. Zinc
C. Platinum
D. Silver

Answer: C

Platinum is inert and catalytically active for hydrogen.

29The flow of electrons in an external circuit of a galvanic cell is from:

A. Cathode to Anode
B. Anode to Cathode
C. Salt bridge to Anode
D. Solution to Cathode

Answer: B

Electrons flow from anode (oxidation) to cathode (reduction).

30Which of the following is used to maintain electrical neutrality in a galvanic cell?

A. Voltmeter
B. Salt bridge
C. Anode
D. Cathode

Answer: B

Salt bridge allows ion migration to maintain charge balance.

31The electrode potential of the Standard Hydrogen Electrode (SHE) is arbitrarily taken as:

A. 1.00 V
B. 0.00 V
C. -1.00 V
D. 0.50 V

Answer: B

SHE is defined as 0.000 V by convention.

32In the construction of SHE, the concentration of HCl (acid) used is:

A. 0.1 M
B. 1.0 M
C. 2.0 M
D. 0.5 M

Answer: B

SHE uses 1 M H⁺ solution.

33The pressure of H₂ gas maintained in a Standard Hydrogen Electrode is:

A. 1 atm
B. 2 atm
C. 0.5 atm
D. 10 atm

Answer: A

Standard pressure is 1 atm.

34The platinum foil in SHE is coated with _____ to increase the surface area for the gas.

A. Gold dust
B. Platinum black
C. Silver nitrate
D. Copper sulphate

Answer: B

Platinum black is finely divided Pt with high surface area.

35SHE can act as:

A. Only an anode
B. Only a cathode
C. Both anode and cathode depending on the other electrode
D. A salt bridge

Answer: C

SHE can be either depending on the half-cell it is coupled with.

36When SHE acts as a cathode, the reaction occurring is:

A. H₂ → 2H⁺ + 2e⁻
B. 2H⁺ + 2e⁻ → H₂
C. 2H₂O → O₂ + 4H⁺ + 4e⁻
D. H₂ + OH⁻ → H₂O + e⁻

Answer: B

As cathode, reduction of H⁺ to H₂ occurs.

37The temperature required for standard electrode potential measurements is:

A. 0°C
B. 25°C
C. 100°C
D. 37°C

Answer: B. 25°C

Standard temperature is 298 K (25°C).

38The standard reduction potential is measured relative to:

A. Calomel electrode
B. Zinc electrode
C. Standard Hydrogen Electrode
D. Glass electrode

Answer: C

SHE is the primary reference.

39If an electrode has a positive standard reduction potential, it means it is _____ likely to be reduced than H⁺.

A. Less
B. More
C. Equally
D. Not

Answer: B

Positive E° means greater tendency to be reduced compared to H⁺.

40The main drawback of using SHE in routine laboratory work is:

A. It is very cheap
B. It is difficult to maintain 1 atm pressure and 1 M concentration
C. It reacts with all metals
D. It produces too much voltage

Answer: B

Maintaining exact conditions is cumbersome.

41The tendency of an electrode to lose electrons when it is in contact with its own ions is specifically called:

A. Standard reduction potential
B. Standard oxidation potential
C. Electronegativity
D. Electron affinity

Answer: B

Standard oxidation potential is the tendency to lose electrons.

42IUPAC convention suggests that the 'Standard Electrode Potential' always refers to:

A. Oxidation potential
B. Reduction potential
C. Cell potential
D. Ionic potential

Answer: B

IUPAC uses reduction potentials (E°_red).

43A metal with a highly negative standard reduction potential is a:

A. Strong oxidizing agent
B. Strong reducing agent
C. Noble metal
D. Catalyst

Answer: B

Negative E° means easy oxidation → strong reducing agent.

44If E°_red of Zn is -0.76 V and E°_red of Cu is +0.34 V, the standard cell potential (E°_cell) is:

A. 0.42 V
B. 1.10 V
C. -1.10 V
D. -0.42 V

Answer: B. 1.10 V

E°_cell = E°_cathode - E°_anode = 0.34 - (-0.76) = 1.10 V.

45Metals located below Hydrogen in the electrochemical series (positive E°_red):

A. Can displace Hydrogen from acids
B. Cannot displace Hydrogen from acids
C. Are very reactive
D. Act as strong reducing agents

Answer: B

Metals with positive E°_red are less reactive than H, cannot displace H⁺.

46Which of the following is the strongest oxidizing agent?

A. Li⁺ (E° = -3.04 V)
B. F₂ (E° = +2.87 V)
C. Zn²⁺ (E° = -0.76 V)
D. H⁺ (E° = 0.00 V)

Answer: B

Higher reduction potential means stronger oxidizing agent; F₂ has highest.

47Electrode potential depends upon:

A. Nature of metal
B. Concentration of ions
C. Temperature
D. All of the above

Answer: D

Electrode potential varies with metal, concentration, and temperature.

48For a spontaneous chemical reaction, the cell potential (E_cell) must be:

A. Negative
B. Zero
C. Positive
D. Infinite

Answer: C

Spontaneous reaction has positive E_cell.

49The oxidation number of Fe in [Fe(CN)₆]⁴⁻ is:

A. +2
B. +3
C. +6
D. -4

Answer: A. +2

CN⁻ = -1, total 6(-1) = -6, overall -4 → Fe = +2.

50In the Electrochemical series, elements are arranged in order of their:

A. Atomic numbers
B. Standard reduction potentials
C. Atomic masses
D. Boiling points

Answer: B

Electrochemical series arranges elements by standard reduction potential.

✅Practice MCQs — Test 2

🧪 Advanced Concepts

50 MCQs

1The oxidation number of Chromium in CrO₅ (which has a butterfly structure with two peroxy linkages) is:

A. +10
B. +6
C. +4
D. +5

Answer: B

CrO₅ has 4 O atoms as peroxy (each O = -1) and one terminal O = -2. Let 4(-1) + (-2) = -6, so Cr = +6.

2In the Marshall's acid (H₂S₂O₈), the oxidation state of Sulfur is:

A. +7
B. +8
C. +6
D. +4

Answer: C. +6

H₂S₂O₈ has a peroxy linkage (-O-O-), so average S = +6 (two S atoms, total O = 8, 2 H: 2+2x -16=0 → 2x=12 → x=6).

3What is the oxidation number of Iron in the brown ring complex [Fe(H₂O)₅(NO)]SO₄?

A. +2
B. +3
C. +1
D. 0

Answer: C. +1

NO acts as NO⁺ (nitrosonium), so charge of complex cation: Fe + 5(0) + (+1) = +2 → Fe = +1.

4Fractional oxidation states are possible in certain ions. What is the oxidation state of Carbon in C₃O₂ (Carbon suboxide)?

A. +4/3
B. +2
C. 0
D. +2/3

Answer: A. +4/3

C₃O₂: 3x + 2(-2)=0 → 3x=4 → x=4/3.

5In the reaction Cl₂ + 2OH⁻ → Cl⁻ + ClO⁻ + H₂O, Chlorine undergoes:

A. Oxidation only
B. Reduction only
C. Disproportionation
D. Substitution

Answer: C. Disproportionation

Cl₂ (0) gives Cl⁻ (-1) and ClO⁻ (+1) → both oxidation and reduction of same element.

6The oxidation number of Nitrogen in NH₄NO₃ is:

A. -3 and +5
B. +3 and -5
C. +1 for both
D. 0 for both

Answer: A. -3 and +5

NH₄⁺: N = -3; NO₃⁻: N = +5.

7In which of the following compounds does Hydrogen exhibit a -1 oxidation state?

A. HCl
B. CaH₂
C. H₂O
D. NH₃

Answer: B. CaH₂

In metal hydrides, H is -1 (e.g., CaH₂).

8The oxidation state of Iodine in IF₇ is:

A. -7
B. +7
C. +5
D. +1

Answer: B. +7

F is -1, so I = +7.

9In the conversion of Br₂ to BrO₃⁻, the oxidation number of Bromine changes by:

A. 3 units
B. 5 units
C. 6 units
D. 2 units

Answer: B. 5 units

Br₂ (0) to BrO₃⁻ (Br = +5) → change of 5.

10What is the oxidation state of Nickel in [Ni(CO)₄]?

A. +2
B. +4
C. 0
D. -2

Answer: C. 0

CO is neutral ligand, so Ni = 0.

11In the balanced equation xMnO₄⁻ + yC₂O₄²⁻ + zH⁺ → Mn²⁺ + CO₂ + H₂O, the coefficients x, y, z are:

A. 2, 5, 16
B. 5, 2, 8
C. 2, 5, 8
D. 1, 2, 4

Answer: A. 2, 5, 16

2MnO₄⁻ + 5C₂O₄²⁻ + 16H⁺ → 2Mn²⁺ + 10CO₂ + 8H₂O.

12When Cl₂ reacts with HOT concentrated NaOH, the oxidation state of Chlorine in the oxygen-containing product is:

A. +1
B. +3
C. +5
D. +7

Answer: C. +5

Hot concentrated NaOH gives NaClO₃ (Cl = +5).

13In the ion-electron method, if a reaction occurs in a basic medium, we balance Oxygen atoms by adding H₂O and then balance Hydrogen by adding:

A. H⁺
B. OH⁻
C. H₂O to the same side and OH⁻ to the opposite
D. Electrons only

Answer: C

In basic medium, add H₂O to balance O and OH⁻ to balance H.

14In the reaction K₂Cr₂O₇ + 14HCl → 2KCl + 2CrCl₃ + 3Cl₂ + 7H₂O, the number of moles of HCl that act as a reducing agent is:

A. 14
B. 6
C. 8
D. 2

Answer: B. 6

Only 6 Cl⁻ (from 6 HCl) are oxidized to Cl₂.

15Which of the following is a 'Comproportionation' reaction?

A. 2H₂O₂ → 2H₂O + O₂
B. Ag²⁺ + Ag → 2Ag⁺
C. Zn + CuSO₄ → ZnSO₄ + Cu
D. NaOH + HCl → NaCl + H₂O

Answer: B. Ag²⁺ + Ag → 2Ag⁺

Comproportionation: two different oxidation states of same element combine to form an intermediate.

16If the pH of the solution in a Standard Hydrogen Electrode is increased from 0 to 7 (neutrality), the electrode potential becomes:

A. 0.00 V
B. -0.413 V
C. +0.413 V
D. -0.059 V

Answer: B. -0.413 V

E = 0.00 - 0.059 pH = -0.413 V.

17At what pH will the Hydrogen electrode have a potential of -0.118 V?

A. 1
B. 2
C. 0
D. 14

Answer: B. 2

-0.118 = -0.059 × pH → pH = 2.

18If the pressure of H₂ gas in SHE is increased to 2 atm while keeping [H⁺] = 1 M, the potential will:

A. Remain 0.00 V
B. Increase (become positive)
C. Decrease (become negative)
D. Become 1.00 V

Answer: B

E = 0.00 - (0.059/2) log(1/2) = +0.0089 V, slightly positive.

19The potential of a hydrogen electrode in contact with a 0.01 M HCl solution is:

A. -0.118 V
B. -0.059 V
C. +0.059 V
D. 0.00 V

Answer: A. -0.118 V

E = -0.059 log(1/0.01) = -0.059×2 = -0.118 V.

20When SHE is used as an anode against a Copper electrode, the pH of the SHE compartment will _____ as the reaction proceeds.

A. Increase
B. Decrease
C. Stay constant
D. Become 7

Answer: B. Decrease

Anode: H₂ → 2H⁺ + 2e⁻, so H⁺ increases, pH decreases.

21Based on the electrochemical series, which of the following reactions is NOT feasible?

A. Zn + CuSO₄ → ZnSO₄ + Cu
B. Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
C. Cu + 2HCl → CuCl₂ + H₂
D. Mg + H₂SO₄ → MgSO₄ + H₂

Answer: C

Cu is below H in series, cannot displace H⁺.

22A metal 'X' displaces 'Y' from its salt solution but cannot displace 'Z'. The order of their reduction potentials is:

A. X > Y > Z
B. Z > X > Y
C. Y > X > Z
D. Z > Y > X

Answer: B

More reactive (more negative E°) displaces less reactive. X displaces Y → E°_X < E°_Y (more negative). Cannot displace Z → E°_X > E°_Z. So Z > X > Y.

23Which of the following will be the best reducing agent?

A. F⁻
B. Cl⁻
C. Br⁻
D. I⁻

Answer: D. I⁻

I⁻ is most easily oxidized (lowest reduction potential for halogen).

24If E°_red values for A, B, C are +0.5 V, -3.0 V, and -1.2 V respectively, the order of reducing power is:

A. A > C > B
B. B > C > A
C. C > B > A
D. A > B > C

Answer: B

More negative reduction potential = stronger reducing agent. Order: B (-3.0) > C (-1.2) > A (+0.5).

25Can we store Copper Sulphate solution in a Zinc container?

A. Yes, because Zn is less reactive
B. No, because Zn will displace Cu
C. Yes, because no reaction occurs
D. No, because Cu will oxidize the container

Answer: B

Zn is more reactive, will displace Cu from solution.

26In the cell Zn | Zn²⁺ (1M) || H⁺ (1M) | H₂ (1 atm) | Pt, if the concentration of Zn²⁺ is reduced to 0.1 M, the cell potential will:

A. Increase
B. Decrease
C. Remain same
D. Drop to zero

Answer: A

E = E° - (0.059/2) log([Zn²⁺]/[H⁺]²); decreasing Zn²⁺ increases the log term (less negative), so E increases.

27The standard reduction potential of F₂/F⁻ is +2.87 V and that of Li⁺/Li is -3.04 V. The E° for the cell Li | Li⁺ || F₂ | F⁻ is:

A. 5.91 V
B. 0.17 V
C. -5.91 V
D. 2.87 V

Answer: A. 5.91 V

E°_cell = E°_cathode - E°_anode = 2.87 - (-3.04) = 5.91 V.

28Which of the following electrodes will act as the best anode?

A. Ag⁺/Ag (E° = +0.80 V)
B. Mg²⁺/Mg (E° = -2.37 V)
C. Fe²⁺/Fe (E° = -0.44 V)
D. Cu²⁺/Cu (E° = +0.34 V)

Answer: B

Best anode = most negative reduction potential (easiest to oxidize).

29The SHE can be represented as:

A. Pt | H₂(1 atm) | H⁺(1M)
B. H₂(1 atm) | H⁺(1M) | Pt
C. Both A and B depending on usage
D. Pt | H⁺(1M) | H₂(1 atm)

Answer: C

Convention varies; both forms are used.

30During the discharge of a Lead Storage Battery (an application of redox), the density of H₂SO₄:

A. Increases
B. Decreases
C. Remains constant
D. Becomes zero

Answer: B. Decreases

Discharge consumes H₂SO₄ and produces water, so density decreases.

31The oxidation number of Phosphorus in Ba(H₂PO₂)₂ is:

A. +3
B. +1
C. +5
D. -1

Answer: B. +1

H₂PO₂⁻: H=+1, O=-2, total charge -1: 2(+1)+P+2(-2) = -1 → 2+P-4=-1 → P=+1.

32In the reaction 3Br₂ + 6CO₃²⁻ + 3H₂O → 5Br⁻ + BrO₃⁻ + 6HCO₃⁻, Bromine is:

A. Oxidized only
B. Reduced only
C. Both oxidized and reduced
D. Neither

Answer: C

Br₂ (0) to Br⁻ (-1) and BrO₃⁻ (+5) → disproportionation.

33The standard reduction potential of an electrode depends on:

A. The size of the electrode
B. The volume of the solution
C. The temperature and nature of the electrode
D. The depth to which electrode is immersed

Answer: C

E° depends on temperature and the metal/ion couple.

34For the cell reaction Cu²⁺ + Zn → Zn²⁺ + Cu, the standard cell potential is 1.10 V. If the equilibrium constant is K, then:

A. K > 1
B. K < 1
C. K = 1
D. K = 0

Answer: A. K > 1

Positive E° means spontaneous, K > 1.

35A salt bridge is NOT required in which of the following?

A. Daniel Cell
B. Lead-acid storage battery (common electrolyte)
C. Zn-Cu galvanic cell
D. Concentration cell

Answer: B

Lead-acid battery uses same electrolyte for both half-cells, so no salt bridge needed.

36The oxidation number of Carbon in Glucose (C₆H₁₂O₆) is:

A. +4
B. +2
C. 0
D. -4

Answer: C. 0

Average oxidation state: 6x + 12(+1) + 6(-2)=0 → 6x+12-12=0 → x=0.

37Which gas is produced at the anode during the electrolysis of aqueous NaCl?

A. H₂
B. O₂
C. Cl₂
D. Na vapor

Answer: C. Cl₂

Chloride ions are oxidized to Cl₂ at the anode.

38The standard oxidation potential of Zinc is +0.76 V. Its standard reduction potential is:

A. +0.76 V
B. -0.76 V
C. 0.00 V
D. 1.52 V

Answer: B. -0.76 V

Reduction potential = - oxidation potential.

39In the reaction H₂O₂ + Ag₂O → 2Ag + H₂O + O₂, H₂O₂ acts as:

A. Oxidizing agent
B. Reducing agent
C. Dehydrating agent
D. Catalyst

Answer: B. Reducing agent

H₂O₂ (O = -1) is oxidized to O₂ (0), so it is reducing agent.

40The oxidation number of Xe in XeOF₄ is:

A. +4
B. +6
C. +2
D. +8

Answer: B. +6

F = -1, O = -2: Xe + (-2) + 4(-1)=0 → Xe -6=0 → Xe=+6.

41Which of the following metals will NOT dissolve in 1 M H₂SO₄ to give H₂ gas?

A. Fe
B. Al
C. Hg
D. Zn

Answer: C. Hg

Hg is below hydrogen in electrochemical series.

42The number of electrons involved in the reduction of one mole of Cr₂O₇²⁻ to Cr³⁺ is:

A. 3
B. 6
C. 2
D. 1

Answer: B. 6

Cr₂O₇²⁻ (Cr=+6) to 2Cr³⁺ (+3): each Cr gains 3 e⁻, total 6 e⁻.

43The electrode potential of a metal can be increased by:

A. Increasing the concentration of its ions
B. Decreasing the concentration of its ions
C. Increasing the surface area
D. Adding a catalyst

Answer: A

Nernst equation: E = E° + (0.059/n) log[Mⁿ⁺], so increasing [Mⁿ⁺] increases E.

44In the reaction Pb + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O, Pb is:

A. Oxidized
B. Reduced
C. Both A and B
D. Neither

Answer: A. Oxidized

Pb (0) goes to PbSO₄ (Pb²⁺), so oxidized.

45What is the oxidation number of Sulfur in Na₂S₄O₆ (Sodium tetrathionate)?

A. +2
B. +2.5
C. +6
D. +4

Answer: B. +2.5

2(+1)+4x+6(-2)=0 → 2+4x-12=0 → 4x=10 → x=2.5 average.

46If the E°_red of an electrode is very high and positive, it is a:

A. Strong reducing agent
B. Strong oxidizing agent
C. Noble metal
D. Good conductor

Answer: B. Strong oxidizing agent

High positive E°_red means it readily gains electrons (oxidizing agent).

47Which element has the highest oxidation state in KMnO₄, K₂Cr₂O₇, and KClO₄?

A. Mn
B. Cr
C. Cl
D. Both Mn and Cl

Answer: D

Mn = +7, Cr = +6, Cl = +7, so Mn and Cl tie.

48In the electrochemical cell Zn | Zn²⁺ || Cu²⁺ | Cu, the salt bridge contains KNO₃. The NO₃⁻ ions move towards:

A. Zinc electrode (anode)
B. Copper electrode (cathode)
C. Stay in the bridge
D. The voltmeter

Answer: A

Anions move to the anode (Zn side) to balance positive charge from Zn²⁺ formation.

49The oxidation state of Oxygen in KO₂ (Potassium superoxide) is:

A. -2
B. -1
C. -1/2
D. +1

Answer: C. -1/2

KO₂ contains O₂⁻ (superoxide), each O has -1/2.

50For the reaction Cu → Cu²⁺ + 2e⁻, E° = -0.34 V. This reaction is:

A. Spontaneous
B. Non-spontaneous (at standard state)
C. At equilibrium
D. Fast

Answer: B

Negative reduction potential for Cu²⁺/Cu means Cu is not easily oxidized under standard conditions.

✅Practice MCQs — Test 3

🧪 Exam-Level Questions

50 MCQs

1In the 'Brown Ring' complex [Fe(H₂O)₅(NO)]SO₄, the oxidation state of Iron is +1. This is because NO acts as:

A. NO⁻ (Nitrosyl anion)
B. NO⁺ (Nitrosonium cation)
C. Neutral NO
D. NO₂⁺

Answer: B

NO⁺ has +1 charge, making the complex cation [Fe(H₂O)₅(NO)]²⁺.

2The oxidation state of Sulfur in Marshall's Acid (H₂S₂O₈) is +6. The 'apparent' calculation suggests +7; the discrepancy is due to:

A. Two Sulfur-Sulfur bonds
B. A peroxy linkage (-O-O-)
C. Resonant double bonds
D. Coordinate covalent bonding

Answer: B

The peroxy linkage means two O atoms are in -1 state, not -2, so S remains +6.

3In the compound Fe₀.₉₄O, the oxidation state of Iron is:

A. Exactly +2
B. Exactly +3
C. Non-integer (Average of +2 and +3)
D. +1

Answer: C

Non-stoichiometric compound with Fe²⁺ and Fe³⁺.

4What is the oxidation state of Bromine in Br₃O₈ for the central Bromine atom?

A. +6
B. +4
C. +2
D. +5

Answer: B

Structure O₃Br-Br(O₂)-BrO₃, central Br is +4.

5In which of the following does the transition metal have an oxidation state of zero?

A. [Ni(CN)₄]²⁻
B. [Fe(CO)₅]
C. Cr₂O₃
D. CuSO₄·5H₂O

Answer: B. [Fe(CO)₅]

In metal carbonyls, CO is neutral, metal has 0 oxidation state.

6Bleaching powder (CaOCl₂) contains two Chlorine atoms. Their oxidation states are:

A. -1 and -1
B. +1 and +1
C. -1 and +1
D. 0 and -1

Answer: C

One Cl⁻ (-1) and one OCl⁻ (Cl = +1).

7In the reaction P₄ + 3NaOH + 3H₂O → 3NaH₂PO₂ + PH₃, Phosphorus undergoes:

A. Only Oxidation
B. Only Reduction
C. Disproportionation
D. Comproportionation

Answer: C

P₄ (0) gives H₂PO₂⁻ (P=+1) and PH₃ (P=-3) → both oxidation and reduction.

8The n-factor (number of moles of electrons transferred per mole of substance) for K₂Cr₂O₇ in an acidic medium is:

A. 3
B. 5
C. 6
D. 2

Answer: C. 6

Cr₂O₇²⁻ → 2Cr³⁺, total gain of 6 e⁻.

9What is the n-factor of FeC₂O₄ (Ferrous Oxalate) when it is oxidized to Fe³⁺ and CO₂ by KMnO₄ in acidic medium?

A. 1
B. 2
C. 3
D. 5

Answer: C. 3

Fe²⁺ → Fe³⁺ (1 e⁻) and C₂O₄²⁻ → 2CO₂ (2 e⁻), total 3 e⁻ per FeC₂O₄.

10When 1 mole of MnO₄⁻ is reduced in a neutral/faintly alkaline medium (Bayer's Reagent), the number of Faradays of electricity involved is:

A. 5 F
B. 3 F
C. 1 F
D. 2 F

Answer: B. 3 F

MnO₄⁻ → MnO₂ (Mn +7 to +4), gain of 3 e⁻.

11The relationship between the standard free energy change (ΔG°) and the standard cell potential (E°) is:

A. ΔG° = nFE°
B. ΔG° = -nFE°
C. E° = ΔG°/nF
D. ΔG° = -RT ln E°

Answer: B. ΔG° = -nFE°

ΔG° = -nFE°.

12If the E°_cell for a reaction is negative, the reaction is:

A. Spontaneous and K_c > 1
B. Non-spontaneous and K_c < 1
C. At equilibrium and K_c = 1
D. Exothermic always

Answer: B

Negative E°_cell means non-spontaneous, K < 1.

13At 25°C, for the cell reaction H₂(g) → 2H⁺(aq) + 2e⁻, if the pH is increased by 1 unit, the electrode potential (E_{H₂/H⁺}) changes by:

A. +0.059 V
B. -0.059 V
C. +0.118 V
D. 0.000 V

Answer: A

E = 0.00 - (0.059/2) log([H⁺]²) = -0.059 log[H⁺] = 0.059 pH. Increase pH by 1 → increase E by 0.059 V.

14For the reaction Cu²⁺ + 2e⁻ → Cu, a plot of E_red vs log[Cu²⁺] is a straight line with a slope of:

A. 0.059
B. 0.0295
C. 0.000
D. -0.059

Answer: B. 0.0295

E = E° + (0.059/2) log[Cu²⁺], slope = 0.059/2 = 0.0295.

15If the equilibrium constant K_c for a redox reaction is 10², the E°_cell at 298 K is approximately:

A. 0.059 V
B. 0.118 V
C. 0.0295 V
D. 0.59 V

Answer: A. 0.059 V

E° = (0.059/n) log K; if n=2, E° = (0.059/2)×2 = 0.059 V.

16Which of the following will increase the reduction potential of a Hydrogen electrode?

A. Increasing the pressure of H₂ gas
B. Increasing the concentration of H⁺ ions
C. Increasing the temperature
D. Adding more Platinum foil

Answer: B

E = 0.059 log[H⁺] (for SHE), so higher [H⁺] increases E.

17A Hydrogen electrode is immersed in a solution with pH = 10. Its reduction potential at 25°C is:

A. 0.00 V
B. -0.59 V
C. +0.59 V
D. -0.059 V

Answer: B. -0.59 V

E = -0.059 × pH = -0.59 V.

18If a SHE is used as an anode, the pH of the anodic compartment will:

A. Increase linearly
B. Decrease as H⁺ is produced
C. Remain 0
D. Remain 7

Answer: B

Anode: H₂ → 2H⁺ + 2e⁻, so H⁺ concentration increases, pH decreases.

19Why is Platinum used in the SHE?

A. It acts as a catalyst for H₂ ⇌ 2H⁺ + 2e⁻
B. It has a high oxidation potential
C. It reacts with HCl to produce electrons
D. It is the cheapest noble metal

Answer: A

Pt is inert and catalyzes the hydrogen redox reaction.

20Which of the following metals can displace Hydrogen from COLD water?

A. Fe
B. Mg
C. Na
D. Al

Answer: C. Na

Na reacts vigorously with cold water to produce H₂.

21Metals with a very high negative reduction potential (e.g., Li, K, Ca) are prepared by:

A. Electrolysis of their aqueous salt solutions
B. Electrolysis of their fused (molten) salts
C. Reduction with carbon
D. Displacement with Copper

Answer: B

In aqueous solution, water would be reduced instead; fused salt electrolysis is used.

22Which of the following is the strongest Reducing Agent in aqueous solution?

A. Li
B. F₂
C. I₂
D. Na

Answer: A. Li

Li has the most negative reduction potential (-3.04 V).

23Under standard conditions, can Fe³⁺ oxidize I⁻ to I₂? (E°_Fe³⁺/Fe²⁺ = +0.77 V, E°_I₂/I⁻ = +0.54 V)

A. Yes, because E°_cell is positive
B. No, because E°_cell is negative
C. Only at high temperatures
D. Fe³⁺ is a reducing agent

Answer: A

E°_cell = 0.77 - 0.54 = +0.23 V > 0, so spontaneous.

24When a Zinc piece is placed in CuSO₄ solution, the Copper is precipitated. If a Copper piece is placed in ZnSO₄ solution:

A. Zinc is precipitated
B. No reaction occurs
C. Hydrogen gas is evolved
D. The solution turns blue

Answer: B

Cu is less reactive than Zn, cannot displace Zn.

25Which of the following ions is most difficult to reduce?

A. Cu²⁺
B. Ag⁺
C. Li⁺
D. H⁺

Answer: C. Li⁺

Li⁺ has the most negative reduction potential, hardest to reduce.

26In the balancing of MnO₄⁻ + Fe²⁺ + H⁺ → Mn²⁺ + Fe³⁺ + H₂O, the ratio of coefficients of Fe²⁺ to MnO₄⁻ is:

A. 1:5
B. 5:1
C. 2:5
D. 5:2

Answer: B. 5:1

5Fe²⁺ + MnO₄⁻ + 8H⁺ → 5Fe³⁺ + Mn²⁺ + 4H₂O → ratio 5:1.

27In a basic medium, when Cl₂ disproportionates, the products are Cl⁻ and ClO₃⁻. How many electrons are transferred per mole of Cl₂ reacting to form ClO₃⁻?

A. 2
B. 5
C. 10
D. 6

Answer: C. 10

Cl₂ (0) → 2ClO₃⁻ (each Cl = +5), total 10 e⁻ per Cl₂.

28The oxidation number of Oxygen in F₂O is +2. This confirms that:

A. Oxygen is more electronegative than Fluorine
B. Fluorine is more electronegative than Oxygen
C. It is a peroxide
D. The molecule is linear

Answer: B

F is more electronegative, so F = -1, O = +2.

29Which of the following remains constant during the operation of a Galvanic cell?

A. Concentration of electrolytes
B. Mass of electrodes
C. Total charge in the universe
D. Temperature of the cell (ideally)

Answer: D

Charge is conserved (first law), but temperature is ideally constant.

30The 'Electrode Potential' is an:

A. Extensive property
B. Intensive property
C. Path function
D. Colligative property

Answer: B

Electrode potential does not depend on amount of material.

31A concentration cell is a cell in which:

A. Two different metals are used
B. Two different concentrations of the same electrolyte are used
C. Only gas electrodes are used
D. No salt bridge is required

Answer: B

Concentration cell has same electrodes but different ion concentrations.

32For a concentration cell Zn | Zn²⁺(C₁) || Zn²⁺(C₂) | Zn to be spontaneous:

A. C₁ = C₂
B. C₁ > C₂
C. C₂ > C₁
D. C₁ = 0

Answer: C

Electrons flow from lower concentration to higher concentration; spontaneous when C₂ > C₁.

33In the electrochemical series, as we move from top to bottom (negative to positive E°):

A. Oxidizing power increases
B. Reducing power increases
C. Electropositivity increases
D. Reactivity with acids increases

Answer: A

Higher (more positive) E° means stronger oxidizing agent.

34Which gas is evolved at the cathode when an aqueous solution of K₂SO₄ is electrolyzed?

A. O₂
B. H₂
C. SO₂
D. K vapor

Answer: B. H₂

Water is reduced to H₂ at cathode because K⁺ is not easily reduced.

35Standard Hydrogen Electrode is a:

A. Primary Reference Electrode
B. Secondary Reference Electrode
C. Indicator Electrode
D. Metal-Metal Ion Electrode

Answer: A

SHE is the primary reference.

36In a Lead Storage Battery, during discharging, the Anode is:

A. PbO₂
B. Pb
C. PbSO₄
D. Platinum

Answer: B. Pb

Anode reaction: Pb + SO₄²⁻ → PbSO₄ + 2e⁻.

37When a Lead Storage battery is recharged:

A. PbSO₄ at anode is reduced to Pb
B. PbSO₄ at cathode is oxidized to PbO₂
C. Sulphuric acid is consumed
D. Both A and B

Answer: D

Recharging reverses discharge reactions.

38The process of 'Passivation' of metals like Al and Cr in HNO₃ is due to:

A. Formation of a soluble nitrate layer
B. Formation of a thin, non-porous oxide layer
C. High reduction potential of the metal
D. Reaction with H₂ gas

Answer: B

A protective oxide layer prevents further reaction.

39In the corrosion of Iron (Rusting), the cathode is:

A. The pure Iron spot
B. The impure Iron spot (or site with less O₂)
C. The site with higher Oxygen concentration
D. The water droplet

Answer: C

Cathode is where oxygen reduction occurs (higher O₂ concentration).

40To prevent the corrosion of Iron pipes underground, they are connected to a block of Magnesium. This is called:

A. Galvanization
B. Cathodic protection (Sacrificial Anode)
C. Electroplating
D. Anodizing

Answer: B

Magnesium acts as sacrificial anode, corroding instead of iron.

41The E°_cell for Cu-Ag cell is 0.46 V. If E°_Ag is 0.80 V, then E°_Cu is:

A. 1.26 V
B. 0.34 V
C. -0.34 V
D. 0.46 V

Answer: B. 0.34 V

E°_cell = E°_cathode - E°_anode. For Cu-Ag, Ag is cathode (0.80), Cu is anode. So 0.46 = 0.80 - E°_Cu → E°_Cu = 0.34 V.

42Which of the following shows the highest increase in oxidation number for Nitrogen?

A. NH₃ → NO
B. N₂H₄ → N₂
C. NO → NO₂
D. NH₃ → HNO₃

Answer: D

NH₃ (-3) to HNO₃ (+5) change of 8.

43The oxidation state of Sulfur in S₄O₆²⁻ (Tetrathionate) is:

A. +2 only
B. +5 and 0
C. +2.5 average
D. Both B and C

Answer: D

Two central S atoms are 0, two terminal S are +5, average = (0+0+5+5)/4 = 2.5.

44What is the potential of the cell Pt | H₂(1 atm) | NaOH(1M) || HCl(1M) | H₂(1 atm) | Pt?

A. 0.00 V
B. 0.826 V
C. 0.059 V
D. 1.10 V

Answer: B. 0.826 V

E = 0.059 × (pH difference) = 0.059 × 14 = 0.826 V.

45If the E_red of an electrode is -0.76 V, its E_ox is:

A. -0.76 V
B. +0.76 V
C. 0.00 V
D. 1.52 V

Answer: B. +0.76 V

E_ox = -E_red.

46Which element cannot have a positive oxidation state?

A. O
B. N
C. F
D. I

Answer: C. F

Fluorine is most electronegative, always -1.

47For the cell Mg | Mg²⁺ || Ag⁺ | Ag, the balanced net cell reaction involves:

A. 1 electron
B. 2 electrons
C. 3 electrons
D. 0 electrons

Answer: B. 2 electrons

Mg → Mg²⁺ + 2e⁻, Ag⁺ + e⁻ → Ag, so 2 electrons total.

48An increase in the concentration of reactants in a spontaneous redox reaction will:

A. Increase E_cell
B. Decrease E_cell
C. Not affect E_cell
D. Make E_cell zero

Answer: A

Nernst equation: E = E° - (0.059/n) log(Q); increasing reactants decreases Q, so E increases.

49The unit of the Faraday constant is:

A. C/mol
B. C/s
C. V/mol
D. J/C

Answer: A. C/mol

Faraday = 96485 C/mol.

50For the half-reaction MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O, if the concentration of H⁺ is doubled, the E_red will:

A. Increase
B. Decrease
C. Remain same
D. Become zero

Answer: A

E = E° - (0.059/5) log([Mn²⁺]/[MnO₄⁻][H⁺]⁸); increasing [H⁺] makes log term smaller (more negative), so E increases.

📄Past Paper MCQs

📅 Actual MDCAT / NUMS Questions

50 MCQs

1The oxidation number of Chromium in K₂Cr₂O₇ is:

MDCAT 2014

A. +3
B. +5
C. +6
D. +7

Answer: C. +6

K₂Cr₂O₇: 2(+1)+2x+7(-2)=0 → 2+2x-14=0 → 2x=12 → x=+6.

2In which of the following compounds does Oxygen show an oxidation state of +2?

MDCAT 2018

A. H₂O₂
B. OF₂
C. KO₂
D. O₃

Answer: B. OF₂

OF₂: F is more electronegative (-1), so O = +2.

3The oxidation state of Sulfur in Na₂S₄O₆ is:

NUMS 2021

A. +2
B. +2.5
C. +4
D. +6

Answer: B. +2.5

Average: 2(+1)+4x+6(-2)=0 → 2+4x-12=0 → 4x=10 → x=2.5.

4In the reaction 2FeCl₃ + SnCl₂ → 2FeCl₂ + SnCl₄, the reducing agent is:

UHS 2011

A. FeCl₃
B. FeCl₂
C. SnCl₂
D. SnCl₄

Answer: C. SnCl₂

SnCl₂ (Sn²⁺ to Sn⁴⁺) loses electrons, so it is reducing agent.

5Which of the following is a disproportionation reaction?

MDCAT 2022

A. 2H₂ + O₂ → 2H₂O
B. Cl₂ + 2OH⁻ → Cl⁻ + ClO⁻ + H₂O
C. CaCO₃ → CaO + CO₂
D. Zn + CuSO₄ → ZnSO₄ + Cu

Answer: B

Cl₂ (0) gives Cl⁻ (-1) and ClO⁻ (+1).

6The oxidation number of Nitrogen in NH₄NO₃ is:

NUMS 2019

A. -3 and +5
B. -3 and -3
C. +3 and +5
D. +5 and +5

Answer: A

NH₄⁺: N = -3; NO₃⁻: N = +5.

7In the reaction MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O, Manganese is:

MDCAT 2015

A. Oxidized
B. Reduced
C. Acting as a reducing agent
D. Neither

Answer: B. Reduced

Mn from +7 to +2, gain of electrons, reduced.

8The oxidation state of Carbon in C₁₂H₂₂O₁₁ (Sucrose) is:

MDCAT 2020

A. +4
B. +2
C. 0
D. -4

Answer: C. 0

12x + 22(+1) + 11(-2)=0 → 12x+22-22=0 → x=0.

9In the 'Brown Ring' complex [Fe(H₂O)₅NO]SO₄, the oxidation state of Fe is:

NUMS 2023

A. +1
B. +2
C. +3
D. 0

Answer: A. +1

NO⁺ makes complex [Fe(H₂O)₅NO]²⁺, so Fe = +1.

10When KMnO₄ is reduced to MnO₂ in a neutral medium, the change in oxidation state is:

UHS 2013

A. 5 units
B. 3 units
C. 2 units
D. 1 unit

Answer: B. 3 units

Mn +7 to +4, change of 3.

11The standard electrode potential of SHE is taken as:

MDCAT 2012

A. 1.0 V
B. 0.0 V
C. -1.0 V
D. 0.5 V

Answer: B. 0.0 V

SHE is reference with potential 0.000 V.

12In SHE, the Platinum foil is coated with Platinum black to:

NUMS 2020

A. Prevent corrosion
B. Increase the surface area for adsorption of H₂
C. Act as a cathode only
D. Absorb HCl

Answer: B

Platinum black provides large surface area.

13Standard conditions for SHE are:

MDCAT 2017

A. 273 K, 1 atm, 1 M HCl
B. 298 K, 1 atm, 1 M HCl
C. 298 K, 1 atm, 0.1 M HCl
D. 373 K, 1 atm, 1 M HCl

Answer: B

25°C, 1 atm, 1 M H⁺.

14If SHE is used as an anode, the cell reaction is:

MDCAT 2021

A. 2H⁺ + 2e⁻ → H₂
B. H₂ → 2H⁺ + 2e⁻
C. H₂ + 2OH⁻ → 2H₂O + 2e⁻
D. 2H₂O → O₂ + 4H⁺ + 4e⁻

Answer: B

As anode, oxidation of H₂ occurs.

15When SHE is coupled with a Zinc electrode (E° = -0.76 V), SHE acts as:

UHS 2016

A. Anode
B. Cathode
C. Salt bridge
D. Inert container

Answer: B

Zn has more negative potential, so it is anode; SHE is cathode.

16The potential of a hydrogen electrode increases if:

NUMS 2022

A. pH of the solution is increased
B. pH of the solution is decreased
C. Pressure of H₂ is decreased
D. Temperature is decreased

Answer: B

E = -0.059 pH, so lower pH (higher [H⁺]) increases E.

17Why is Platinum used in SHE?

MDCAT 2019

A. It is very reactive
B. It provides a surface for electron transfer and is inert
C. It is a liquid at room temperature
D. It is a good oxidizing agent

Answer: B

Pt is inert and catalytically active.

18The E° of an electrode measured against SHE is called:

MDCAT 2015

A. Absolute potential
B. Standard electrode potential
C. Ionization potential
D. Contact potential

Answer: B

Standard electrode potential is measured relative to SHE.

19Which of the following is the strongest oxidizing agent?

MDCAT 2023

A. F₂
B. Cl₂
C. Li
D. I₂

Answer: A. F₂

F₂ has highest reduction potential (+2.87 V).

20A metal which can displace Hydrogen from acids must have a standard reduction potential that is:

UHS 2012

A. Positive
B. Negative
C. Zero
D. Greater than +0.80 V

Answer: B

Metals with negative E° (below H in series) displace H⁺.

21Elements at the top of the electrochemical series (most negative E°) are:

MDCAT 2016

A. Strong oxidizing agents
B. Strong reducing agents
C. Noble metals
D. Least reactive

Answer: B

Most negative E° means easiest to oxidize → strong reducing agents.

22Which metal can be displaced by Zn from its salt solution?

NUMS 2020

A. Mg
B. Na
C. Cu
D. Ca

Answer: C. Cu

Zn is more reactive than Cu, can displace Cu.

23The E°_red values for three metals X, Y, Z are -1.2 V, +0.5 V, and -3.0 V. The order of reactivity is:

MDCAT 2022

A. Y > X > Z
B. Z > X > Y
C. Z > Y > X
D. X > Y > Z

Answer: B

More negative = more reactive, so Z (-3.0) > X (-1.2) > Y (+0.5).

24Which of the following reactions is NOT feasible?

UHS 2014

A. Zn + CuSO₄ → ZnSO₄ + Cu
B. Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
C. Cu + ZnSO₄ → CuSO₄ + Zn
D. Mg + 2HCl → MgCl₂ + H₂

Answer: C

Cu cannot displace Zn because Cu is less reactive.

25Fluorine is a stronger oxidizing agent than Chlorine because of its:

MDCAT 2021

A. High hydration energy
B. Low dissociation energy
C. High electronegativity
D. All of these

Answer: D

All factors contribute to F₂'s strong oxidizing power.

26In a galvanic cell, the salt bridge is used to:

MDCAT 2018

A. Increase the voltage
B. Maintain electrical neutrality
C. Stop the reaction
D. Connect the two electrodes directly

Answer: B

Salt bridge allows ion flow to maintain charge balance.

27For a spontaneous reaction, the E°_cell must be:

NUMS 2021

A. Negative
B. Zero
C. Positive
D. Infinite

Answer: C. Positive

Spontaneous reaction has positive E°_cell.

28In an electrolytic cell, the cathode is the electrode where:

UHS 2015

A. Oxidation occurs and it is positive
B. Reduction occurs and it is negative
C. Oxidation occurs and it is negative
D. Reduction occurs and it is positive

Answer: B

In electrolytic cell, cathode is negative and reduction occurs.

29The standard cell potential for Zn-Cu cell (E°_Zn = -0.76 V, E°_Cu = +0.34 V) is:

MDCAT 2013

A. 0.42 V
B. 1.10 V
C. -1.10 V
D. 1.52 V

Answer: B. 1.10 V

E°_cell = 0.34 - (-0.76) = 1.10 V.

30During the electrolysis of aqueous NaCl, the gas evolved at the anode is:

MDCAT 2020

A. H₂
B. O₂
C. Cl₂
D. Na vapor

Answer: C. Cl₂

Cl⁻ is oxidized to Cl₂ at anode.

31The cell potential (E_cell) depends on:

NUMS 2019

A. Temperature
B. Concentration of ions
C. Nature of electrodes
D. All of these

Answer: D

Nernst equation shows dependence on T, concentration, and nature.

32In a concentration cell, the E°_cell is always:

MDCAT 2023

A. Positive
B. Negative
C. Zero
D. 1.1 V

Answer: C. Zero

Same electrodes, so E° = 0.

33How many electrons are lost by one mole of Fe²⁺ when it is oxidized to Fe³⁺?

MDCAT 2011

A. 1 mole of electrons
B. 2 moles of electrons
C. 3 moles of electrons
D. 6.02 × 10²³ electrons

Answer: D. 6.02 × 10²³ electrons

1 mol Fe²⁺ loses 1 mol e⁻ = 6.02×10²³ electrons.

34In the balanced equation MnO₄⁻ + 5Fe²⁺ + 8H⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O, the coefficient of H⁺ is:

UHS 2017

A. 4
B. 8
C. 5
D. 2

Answer: B. 8

From the equation, 8 H⁺.

35A Lead Storage Battery is an example of:

MDCAT 2019

A. Primary cell
B. Secondary cell
C. Fuel cell
D. Electrolytic cell

Answer: B. Secondary cell

Lead-acid battery is rechargeable (secondary cell).

36In the corrosion of Iron, the anode is:

MDCAT 2022

A. Oxygen-rich area
B. Oxygen-poor area
C. Water droplet
D. Salt bridge

Answer: B. Oxygen-poor area

Anodic area is where Fe oxidizes (oxygen-poor).

37Which metal is used for the 'Galvanization' of Iron?

NUMS 2018

A. Cu
B. Zn
C. Al
D. Sn

Answer: B. Zn

Zinc coating protects iron.

38The process of using electricity to split a compound is:

UHS 2010

A. Hydrolysis
B. Electrolysis
C. Photolysis
D. Thermolysis

Answer: B. Electrolysis

Electrolysis uses electricity to decompose.

39In the reaction Cl₂ + 2KI → 2KCl + I₂, Chlorine is:

MDCAT 2014

A. Oxidized
B. Reduced
C. Acts as a reducing agent
D. Catalyst

Answer: B. Reduced

Cl₂ (0) to Cl⁻ (-1) gains electrons, reduced.

40The oxidation number of Mn in K₂MnO₄ is:

MDCAT 2021

A. +7
B. +6
C. +4
D. +2

Answer: B. +6

K₂MnO₄: 2(+1)+x+4(-2)=0 → 2+x-8=0 → x=+6.

41One Faraday of electricity is equal to:

NUMS 2020

A. 96500 C
B. 1.6×10⁻¹⁹ C
C. 1 C
D. 6.02×10²³ C

Answer: A. 96500 C

1 F = 96485 C ≈ 96500 C.

42Which metal is found in nature in the free state due to its high reduction potential?

MDCAT 2016

A. Na
B. Al
C. Au
D. Mg

Answer: C. Au

Gold is unreactive (positive E°), found native.

43For the reaction Cu → Cu²⁺ + 2e⁻, the E° is -0.34 V. This process is:

MDCAT 2022

A. Spontaneous
B. Non-spontaneous
C. At equilibrium
D. Fast

Answer: B

Negative reduction potential for Cu²⁺/Cu means Cu oxidation is non-spontaneous.

44Oxidation number of Oxygen in O₃ is:

UHS 2015

A. -2
B. -1
C. 0
D. +1

Answer: C. 0

Ozone is elemental form, oxidation state 0.

45In the reaction AgNO₃ + NaCl → AgCl + NaNO₃, the oxidation state of Silver:

NUMS 2021

A. Increases
B. Decreases
C. Remains same
D. Becomes zero

Answer: C

This is not a redox reaction; Ag remains +1.

46Which of the following can act as both an oxidizing and a reducing agent?

MDCAT 2023

A. KMnO₄
B. H₂O₂
C. K₂Cr₂O₇
D. HNO₃

Answer: B. H₂O₂

H₂O₂ can be oxidized to O₂ or reduced to H₂O.

47The passage of electricity through an electrolyte is due to the movement of:

MDCAT 2018

A. Electrons
B. Protons
C. Ions
D. Atoms

Answer: C. Ions

In electrolyte, current is carried by ions.

48In the cell Zn | Zn²⁺ || Cu²⁺ | Cu, the flow of electrons is from:

UHS 2011

A. Cu to Zn
B. Zn to Cu
C. Salt bridge to Zn
D. Cu²⁺ to Zn²⁺

Answer: B. Zn to Cu

Zn is anode, electrons flow from Zn to Cu.

49Standard reduction potential of Li⁺/Li is the most negative, which means Li is the:

NUMS 2020

A. Weakest reducing agent
B. Strongest reducing agent
C. Strongest oxidizing agent
D. Most noble metal

Answer: B. Strongest reducing agent

Most negative E° = strongest reducing agent.

50The oxidation state of Ni in [Ni(CO)₄] is:

MDCAT 2022

A. 0
B. +2
C. +4
D. -2

Answer: A. 0

CO is neutral ligand, so Ni = 0.

🔍Direct Search Queries — Electrochemistry

Exact search terms students use on Google for this chapter. Click any to jump to the relevant section:

electrochemistry MDCAT notes redox reactions explained oxidation number rules oxidation vs reduction oxidising and reducing agents how to find oxidation number cathode and anode difference electrode potential definition Standard Hydrogen Electrode construction SHE working principle standard electrode potential table electrochemical series explanation Nernst equation derivation galvanic cell vs electrolytic cell salt bridge function what is a redox reaction define oxidation and reduction what is SHE in chemistry what is standard electrode potential difference between cathode and anode what is disproportionation reaction electrochemistry MCQs with answers electrochemistry MCQs pdf oxidation number MCQs MDCAT past papers electrochemistry NUMS chemistry past papers UHS chemistry MCQs electrochemistry chapter notes class 11 redox reactions class 11 chemistry SHE class 11 notes electrode potential class 11 chemistry

❔Frequently Asked Questions

What is a redox reaction?

A redox reaction is a chemical reaction in which oxidation and reduction occur simultaneously. One species loses electrons (is oxidised) while another gains electrons (is reduced).

How is oxidation defined in terms of oxidation number?

Oxidation is an increase in oxidation number. Reduction is a decrease in oxidation number.

What is the difference between an oxidising agent and a reducing agent?

An oxidising agent gains electrons and is itself reduced (its oxidation number decreases). A reducing agent loses electrons and is itself oxidised (its oxidation number increases).

What are the rules for assigning oxidation numbers?

Free elements = 0; monatomic ions = their charge; oxygen = -2 (except peroxides -1, OF2 +2); hydrogen = +1 (except metal hydrides -1); sum in neutral compound = 0, in polyatomic ion = ion charge.

What is the cathode and anode in an electrochemical cell?

Cathode is the electrode where reduction occurs. Anode is the electrode where oxidation occurs. In a galvanic cell, cathode is positive and anode is negative; in an electrolytic cell, cathode is negative and anode is positive.

What is electrode potential?

Electrode potential is the potential difference developed between an electrode and its ion solution. It measures the tendency of the electrode to gain or lose electrons.

What is the Standard Hydrogen Electrode (SHE)?

SHE is the reference electrode used to measure standard electrode potentials. It consists of a platinum electrode in 1 M H+ solution with H2 gas at 1 atm and 25°C. Its potential is defined as 0.00 V.

What is standard electrode potential?

Standard electrode potential (E°) is the potential of an electrode measured against SHE under standard conditions (1 M concentration, 1 atm pressure, 25°C).

What does a positive E° mean?

A positive E° means the electrode has a greater tendency to be reduced than H+; it is a stronger oxidising agent. A negative E° means it is a stronger reducing agent.

How is cell potential calculated?

E°cell = E°cathode − E°anode (using reduction potentials). For a spontaneous reaction, E°cell must be positive.

What is the electrochemical series?

The electrochemical series arranges elements by their standard reduction potentials. Elements with more negative E° are stronger reducing agents; those with more positive E° are stronger oxidising agents.

What is the Nernst equation?

E = E° − (RT/nF) ln Q, or at 25°C E = E° − (0.059/n) log Q. It relates cell potential to concentrations of reactants and products.

What is a disproportionation reaction?

A disproportionation reaction is a redox reaction in which the same element undergoes both oxidation and reduction. Example: Cl2 + 2OH− → Cl− + ClO− + H2O.

What is a galvanic cell?

A galvanic (voltaic) cell converts chemical energy into electrical energy. It consists of two half-cells connected by a salt bridge, with spontaneous redox reactions producing a positive cell potential.

What is the role of a salt bridge?

A salt bridge maintains electrical neutrality by allowing ions to migrate between the two half-cells, completing the circuit.

How does the oxidation number of an element in a free state differ from that in a compound?

In its free elemental state, the oxidation number is 0. In compounds, it can be positive, negative, or zero depending on the element and its bonding.

What is the oxidation number of oxygen in peroxides?

In peroxides (e.g., H2O2), oxygen has an oxidation number of −1. In most other compounds, it is −2.

What is the strongest oxidising agent among the halogens?

Fluorine (F2) is the strongest oxidising agent among the halogens due to its highest standard reduction potential (+2.87 V).

How many MCQs come from Electrochemistry in MDCAT?

Electrochemistry typically contributes 3–5 MCQs out of 81 Chemistry MCQs in MDCAT.

Which topics from Electrochemistry are most frequently asked in MDCAT?

Oxidation number calculations, identifying oxidation/reduction, oxidising/reducing agents, SHE construction, standard electrode potentials, cell potential calculations, and the electrochemical series.

Electrochemistry — Complete MDCAT Notes & MCQs

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❓People Also Ask — Electrochemistry

📋Syllabus & Learning Outcomes

📝Full Notes — Electrochemistry

⚡ Electrochemistry – Schematic Notes

🔄 1. Characteristics of Redox Reactions

🔢 2. Oxidation Number – Definition of Oxidation & Reduction

📏 Oxidation Number Rules (Key)

🧮 3. Identifying Oxidation & Reduction

🔌 4. Electrochemical Terms

⚡ 5. Standard Electrode Potential (E°)

⚡ Cations/Potentials comparison (Positive E°):

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