Electrochemistry Numericals – Complete Guide for Competitive Exams
Electrochemistry numericals are among the most scoring problems in Class 11 & 12 Chemistry. Almost every competitive exam such as NEET, JEE Main, JEE Advanced, CUET, IIT-JAM includes direct or indirect numerical questions from this chapter.
Table of Contents
- Importance of Electrochemistry Numericals
- Important Electrochemistry Formulas
- Numericals Based on Faraday’s Laws
- Nernst Equation Numericals
- Conductance & Cell Constant Problems
- EMF & Gibbs Free Energy Problems
- Exam-Oriented MCQs
- Smart Exam Tips
- Frequently Asked Questions
Importance of Electrochemistry Numericals
Electrochemistry numericals test a student’s understanding of:
- Redox reactions
- Charge transfer
- Electrode potentials
- Thermodynamics connection
Most questions are formula-based and time-efficient, making them ideal for scoring full marks in exams.
Also read: Laws of Thermodynamics | Introduction to Electrochemistry
Important Electrochemistry Formulas
| Concept | Formula |
|---|---|
| Charge | Q = I × t |
| Faraday’s Law | m = (Q × M) / (n × F) |
| Nernst Equation | E = E° − (0.0591/n) log Q |
| Gibbs Free Energy | ΔG° = −nFE° |
| Conductivity | κ = (1/R) × (l/A) |
Numericals Based on Faraday’s Laws
Example 1
Calculate the mass of copper deposited when a current of 2 A is passed for 30 minutes through CuSO₄ solution.
Solution:
- I = 2 A
- t = 30 × 60 = 1800 s
- Q = I × t = 3600 C
- M = 63.5, n = 2
m = (3600 × 63.5) / (2 × 96500) = 1.18 g
Nernst Equation Numericals
Example 2
Calculate the electrode potential at 298 K when concentration of metal ion is 0.01 M. E° = 0.34 V.
Solution:
E = 0.34 − (0.0591/2) log(1/0.01)
E = 0.34 − 0.0591 = 0.2809 V
Conductance & Cell Constant Numericals
These numericals frequently appear in JEE & CUET.
Cell Constant = l / A Conductivity = Cell Constant × Conductance
EMF & Gibbs Free Energy Numericals
Electrochemical cells are directly related to thermodynamics.
ΔG° = −nFE°
If E° is positive → reaction is spontaneous.
Exam-Oriented MCQs
Q1. Value of Faraday constant is:
- A) 96500 C mol⁻¹ ✅
- B) 9650 C
- C) 96.5 C
- D) 1 C
Explanation: One mole of electrons carries charge equal to Faraday constant.
Smart Exam Tips
- Always write units
- Convert time into seconds
- Memorize constants
- Practice previous year questions
Frequently Asked Questions
Is Electrochemistry important for NEET?
Yes, 2–3 questions are asked every year directly from numericals.
Which formula is most important?
Faraday’s Law and Nernst Equation.
CHEMASH provides a complete numerical-solving framework including formulas, concepts, solved examples, MCQs, and exam tips.
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