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Electrochemistry - NEET Previous Year Questions with Complete Solutions

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Team eSaral

eSaral Academic and Editorial Team

7 min read

Summary

Electrochemistry NEET previous year questions test a small set of ideas: electrode potential and reducing power, the Nernst equation, products of electrolysis, Faraday’s laws, conductivity and Kohlrausch’s law, and the relation between Gibbs energy and EMF. This page gives the key formulas, solved previous year questions with step-by-step solutions, practice questions, common mistakes and FAQs for NEET Chemistry.

Electrochemistry

Electrochemistry NEET questions are formula-based and short, so they reward students who know when to use which formula. Use this page after you finish the chapter: first revise the formulas, then solve the previous year questions without looking at the solutions. For the theory, read eSaral’s Electrochemistry notes for NEET (PDF), and for the NCERT questions use eSaral’s NCERT Solutions for Class 12 Chemistry.

Electrochemistry NEET Weightage

NEET Chemistry has 45 questions, and Electrochemistry gives a few of them. According to eSaral’s NEET 2026 paper analysis, Electrochemistry had 3 questions in NEET 2026, the same as Redox Reactions, Hydrocarbons and Carboxylic Acids and Amines, and only Coordination Compounds had more in Chemistry. For the year-wise numbers, see eSaral’s NEET Chemistry weightage page.

Topics Asked in Electrochemistry NEET Previous Year Questions

  1. Standard electrode potential and the order of reducing power
  2. Nernst equation and the EMF of a cell at non-standard concentrations
  3. Products of electrolysis at the anode and the cathode
  4. Faraday’s laws and mass deposited calculations
  5. Conductivity, cell constant, molar conductivity and Kohlrausch’s law
  6. Relation between $\Delta G^\circ$, $E^\circ_{cell}$ and the equilibrium constant
  7. Types of cells: galvanic and electrolytic

Key Formulas for Electrochemistry NEET

Topic

Formula

EMF of a cell

$E^\circ_{cell} = E^\circ_{cathode} - E^\circ_{anode}$

Nernst equation (298 K)

$E_{cell} = E^\circ_{cell} - \dfrac{0.0592}{n}\log Q$

Gibbs energy

$\Delta G^\circ = -nFE^\circ_{cell}$

Equilibrium constant (298 K)

$E^\circ_{cell} = \dfrac{0.0592}{n}\log K$

Faraday’s laws

$m = \dfrac{M\,I\,t}{nF}$, with $F = 96500\ \text{C mol}^{-1}$

Conductivity and cell constant

$\kappa = \dfrac{G^*}{R}$, so $G^* = \kappa R$

Molar conductivity

$\Lambda_m = \dfrac{\kappa \times 1000}{M}$

Kohlrausch’s law

$\Lambda_m = \Lambda_m^\circ - A\sqrt{c}$ (strong electrolytes), and $\Lambda_m^\circ = \nu_+\lambda_+^\circ + \nu_-\lambda_-^\circ$

Daniel cell: anode and cathode reactions, salt bridge, electron flow, cell notation and EMF

In the Daniel cell above, oxidation takes place at the anode (zinc) and reduction at the cathode (copper), so $E^\circ_{cell} = E^\circ_{Cu^{2+}/Cu} - E^\circ_{Zn^{2+}/Zn} = +1.10$ V. Remember it as RED CAT: reduction at the cathode.

Solved Electrochemistry NEET Previous Year Questions

PYQ 1 (NEET 2020): Product at the anode

On electrolysis of dilute sulphuric acid using platinum electrodes, the product obtained at the anode will be: (a) H₂S gas (b) SO₂ gas (c) hydrogen gas (d) oxygen gas.

Solution: In dilute sulphuric acid, water is oxidised at the anode more easily than the sulphate ion:

$$2H_2O \rightarrow O_2 + 4H^+ + 4e^-$$

Answer: (d) oxygen gas. Hydrogen is formed at the cathode.

PYQ 2 (NEET 2019): Order of reducing power

The standard electrode potentials of $Al^{3+}/Al$, $Ag^+/Ag$, $K^+/K$ and $Cr^{3+}/Cr$ are $-1.66$ V, $0.80$ V, $-2.93$ V and $-0.74$ V. Find the correct decreasing order of reducing power of the metals.

Solution: The more negative the $E^\circ$, the stronger the reducing agent: K ($-2.93$) > Al ($-1.66$) > Cr ($-0.74$) > Ag ($+0.80$).

Answer: $K > Al > Cr > Ag$.

PYQ 3 (NEET 2017): Daniel cell with changed concentrations

In the cell $Zn \mid ZnSO_4 (0.01\ \text{M}) \parallel CuSO_4 (1.0\ \text{M}) \mid Cu$, the EMF is $E_1$. When the concentration of $ZnSO_4$ is changed to $1.0$ M and that of $CuSO_4$ to $0.01$ M, the EMF becomes $E_2$. What is the relation between $E_1$ and $E_2$? (Take $\dfrac{2.303RT}{F} = 0.059$.)

Solution: Use the Nernst equation with $n = 2$ and $Q = \dfrac{[Zn^{2+}]}{[Cu^{2+}]}$.

$$E_1 = E^\circ - \frac{0.059}{2}\log\frac{0.01}{1} = E^\circ + 0.059\ \text{V}$$ $$E_2 = E^\circ - \frac{0.059}{2}\log\frac{1}{0.01} = E^\circ - 0.059\ \text{V}$$

Answer: $E_1 > E_2$.

PYQ 4 (NEET 2013): Mass of cobalt deposited

How many grams of cobalt will be deposited when a solution of cobalt(II) chloride is electrolysed with a current of 10 A for 109 minutes? ($1\ F = 96500$ C, atomic mass of Co $= 59$ u)

Solution: The charge is $Q = It = 10 \times 109 \times 60 = 65400$ C. For $Co^{2+} + 2e^- \rightarrow Co$, $n = 2$.

$$m = \frac{M\,Q}{nF} = \frac{59 \times 65400}{2 \times 96500} \approx 20\ \text{g}$$

Answer: about 20 g.

PYQ 5: EMF of a nickel-silver cell

Find the EMF of the cell $Ni(s) + 2Ag^+ (0.001\ \text{M}) \rightarrow Ni^{2+} (0.001\ \text{M}) + 2Ag(s)$. Given $E^\circ_{cell} = 1.05$ V and $\dfrac{2.303RT}{F} = 0.059$ at 298 K. (a) 1.0385 V (b) 1.385 V (c) 0.9615 V (d) 1.05 V

Solution: Here $n = 2$ and $Q = \dfrac{[Ni^{2+}]}{[Ag^+]^2} = \dfrac{0.001}{(0.001)^2} = 1000$.

$$E = 1.05 - \frac{0.059}{2}\log 1000 = 1.05 - 0.0295 \times 3 = 0.9615\ \text{V}$$

Answer: (c) 0.9615 V.

PYQ 6: Cell constant

The conductivity of a centimolar solution of KCl at 25°C is $0.0210\ \Omega^{-1}\text{cm}^{-1}$, and the resistance of the cell containing the solution is $60\ \Omega$. The cell constant is: (a) 3.28 cm⁻¹ (b) 1.26 cm⁻¹ (c) 3.34 cm⁻¹ (d) 1.34 cm⁻¹

Solution: $G^* = \kappa \times R = 0.0210 \times 60 = 1.26\ \text{cm}^{-1}$.

Answer: (b) 1.26 cm⁻¹.

PYQ 7: Time for electrolysis of molten NaCl

During the electrolysis of molten sodium chloride, the time required to produce $0.10$ mol of chlorine gas using a current of 3 A is: (a) 55 minutes (b) 110 minutes (c) 220 minutes (d) 330 minutes

Solution: $2Cl^- \rightarrow Cl_2 + 2e^-$, so $0.10$ mol of $Cl_2$ needs $0.20$ mol of electrons.

$$Q = 0.20 \times 96500 = 19300\ \text{C}, \qquad t = \frac{Q}{I} = \frac{19300}{3} \approx 6433\ \text{s} \approx 107\ \text{min}$$

Answer: (b) 110 minutes (the nearest option).

More Electrochemistry NEET PYQs With Solutions (Images)

The solved questions below are from eSaral’s earlier set of Electrochemistry NEET previous year questions, shown as images.

Practice Questions for Electrochemistry NEET

  1. Find the EMF of the cell $Zn \mid Zn^{2+} (0.1\ \text{M}) \parallel Cu^{2+} (0.01\ \text{M}) \mid Cu$, if $E^\circ_{cell} = 1.10$ V. Take $\dfrac{0.0592}{n} = 0.0296$.
  2. Find the mass of aluminium deposited by $9650$ C of charge. (Atomic mass of Al $= 27$ u)
  3. The limiting molar conductivities of NaCl, HCl and CH₃COONa are $126.4$, $425.9$ and $91.0\ \text{S cm}^2\text{mol}^{-1}$. Find $\Lambda_m^\circ$ of CH₃COOH.

Answers: 1. $E = 1.10 - 0.0296\log\dfrac{0.1}{0.01} = 1.07$ V. 2. $m = \dfrac{27 \times 9650}{3 \times 96500} = 0.9$ g. 3. $\Lambda_m^\circ = 425.9 + 91.0 - 126.4 = 390.5\ \text{S cm}^2\text{mol}^{-1}$.

Common Mistakes in Electrochemistry NEET Questions

Mistake

How to avoid it

Writing $E^\circ_{cell} = E^\circ_{anode} - E^\circ_{cathode}$

Always use $E^\circ_{cell} = E^\circ_{cathode} - E^\circ_{anode}$. The cathode has the higher reduction potential in a spontaneous cell

Including pure solids in $Q$

Only dissolved species (and gases) go in $Q$. For $Zn \mid Zn^{2+} \parallel Cu^{2+} \mid Cu$, $Q = [Zn^{2+}]/[Cu^{2+}]$

Using the wrong $n$

$n$ is the number of electrons in the half-reaction for one ion. It is 2 for $Cu^{2+} \rightarrow Cu$, 3 for $Al^{3+} \rightarrow Al$, and 5 for $MnO_4^- \rightarrow Mn^{2+}$. Write the half-reaction first

Not converting units

Current in A, time in s. $\Delta G^\circ$ comes out in J, so divide by 1000 for kJ

Confusing $\Lambda_m$ and $\Lambda_m^\circ$

$\Lambda_m^\circ$ is at infinite dilution, and $\Lambda_m$ is at the given concentration

Choosing the wrong product at the anode

Compare what is oxidised more easily: the anion or water. In dilute $H_2SO_4$ with Pt electrodes, oxygen is formed

How to Prepare Electrochemistry for NEET

  1. Read the NCERT chapter once, and make a one-page formula sheet like the table above.
  2. Revise with notes: eSaral’s NEET Chemistry notes and the Electrochemistry notes (PDF).
  3. Solve the PYQs on this page, and then the other chapters on eSaral’s NEET chapter-wise previous year questions page. For a related chapter, try the Redox Reactions NEET PYQs.
  4. Practise board-style questions with the Electrochemistry Class 12 important questions if you also need to prepare for the board exam.

Frequently Asked Questions

What is the Electrochemistry NEET weightage?

NEET Chemistry has 45 questions, and Electrochemistry usually gives a few of them. According to eSaral’s NEET 2026 paper analysis, Electrochemistry had 3 questions in NEET 2026. For the year-wise numbers, check eSaral’s NEET Chemistry weightage page.

Which topics are asked in Electrochemistry NEET previous year questions?

The Electrochemistry NEET previous year questions are mostly on electrode potential and the order of reducing power, the Nernst equation, products of electrolysis, Faraday’s laws, conductivity and the cell constant, Kohlrausch’s law, and the relation between

What is the Nernst equation and how is it used in NEET?

The Nernst equation gives the cell EMF when the concentrations are not 1 M: $E_{cell} = E^\circ_{cell} - \dfrac{0.0592}{n}\log Q$ at 298 K. $Q$ is the reaction quotient, with the products in the numerator and the reactants in the denominator. Pure solids and liquids are not included in $Q$.

How do I calculate the mass deposited using Faraday’s first law?

Use $m = \dfrac{M \times I \times t}{n \times F}$, where $M$ is the molar mass, $I$ is the current in amperes, $t$ is the time in seconds, $n$ is the number of electrons for one ion, and $F = 96500\ \text{C mol}^{-1}$. Write the half-reaction first to get $n$.

Is NCERT enough for Electrochemistry NEET questions?

Yes, for most of them. The Electrochemistry chapter of NCERT Class 12 Chemistry covers the Nernst equation, Faraday’s laws, conductivity and Kohlrausch’s law that NEET asks. Solve the in-text examples and the exercise questions, and then practise PYQs. eSaral’s NCERT Solutions for Class 12 Chemistry give step-by-step answers.

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

A galvanic cell converts the energy of a spontaneous redox reaction into electrical energy, and the cathode is the positive electrode. An electrolytic cell uses electrical energy to force a non-spontaneous reaction, and the cathode is the negative electrode. In both cells, oxidation takes place at the anode and reduction at the cathode.

How do you find the product of electrolysis at the anode?

Compare the species that can be oxidised at the anode and choose the one that is oxidised more easily. For dilute sulphuric acid with platinum electrodes, water is oxidised, so oxygen gas is formed at the anode: $2H_2O \rightarrow O_2 + 4H^+ + 4e^-$.

How do you find the order of reducing power from standard electrode potentials?

The lower (more negative) the $E^\circ$ value, the stronger the reducing agent. For example, with $E^\circ$ values of $-2.93$ V for K, $-1.66$ V for Al, $-0.74$ V for Cr and $+0.80$ V for Ag, the reducing power is $K > Al > Cr > Ag$.

What is the relation between $\Delta G^\circ$ and $E^\circ_{cell}$?

$\Delta G^\circ = -nFE^\circ_{cell}$, so a positive $E^\circ_{cell}$ means a negative $\Delta G^\circ$ and a spontaneous reaction. $\Delta G^\circ$ comes out in joules, so divide by 1000 for kJ. At 298 K, $E^\circ_{cell} = \dfrac{0.0592}{n}\log K$.

What are molar conductivity and Kohlrausch’s law?

Molar conductivity is $\Lambda_m = \dfrac{\kappa \times 1000}{M}$, where $\kappa$ is the conductivity and $M$ is the molarity. Kohlrausch’s law of independent migration states that the limiting molar conductivity of an electrolyte is the sum of the contributions of its ions: $\Lambda_m^\circ = \nu_+\lambda_+^\circ + \nu_-\lambda_-^\circ$.

How do I solve Electrochemistry NEET numericals quickly?

Write the cell reaction or the half-reaction, find $n$, convert the units (current in A, time in s), and then substitute in the right formula. Most Electrochemistry NEET numericals use only the Nernst equation, Faraday’s laws, $\Delta G^\circ = -nFE^\circ$ and $\Lambda_m$. Practise them with the PYQs on this page.

Where can I find more Electrochemistry NEET PYQs and notes?

eSaral has Electrochemistry notes for NEET (PDF), the NEET chapter-wise previous year questions page, NEET Chemistry notes and the Class 12 Electrochemistry important questions. All of them are linked on this page.

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Team eSaral

eSaral Academic and Editorial Team

Team eSaral is the collective author profile for educational content created by eSaral’s teachers and academic contributors. The team draws on expertise from IIT graduates, doctors, experienced educators and subject specialists to develop resources for JEE, NEET and school students. Our articles aim to explain concepts clearly and help students study with confidence.

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