JEE Main · Chemistry · Electrochemistry

Faraday's Laws of Electrolysis: JEE Main previous year questions

Name: Faraday's Laws of Electrolysis: JEE Main previous year questions
Creator: Lumi

16 questions in the 108 JEE Main shifts Lumi analysed, in 6 of 8 years. Pattern: Asked most years. 7 came in 2024–26. Here is how it is asked and which ideas come back.

Questions: 16; in 16 of 108 shifts
Years asked: 6/8; last asked 2025
Chance in a shift: 19%; calibrated model, how we compute it
Weighted estimate: 0.1; model; history: 0.1 a shift on average, typically 0.0–0.3

Key findings

01
Asked in 6 of 8 years with analysed shifts and in 16 of 108 shifts: 16 questions, #154 of 196 topics. Last asked in 2025.
02
56% of its questions since 2020 tested an idea no earlier year had asked; 2 repeated an idea from the year before.
03
The most repeated idea is Charge-Mole Relationship, asked 4 times in 4 shifts (2021, 2022, 2024), most often as “moles liberated per faraday”.
04
JEE Main has asked 9 of the 49 ideas in this topic; 36 have never been asked, directly or inside another question.
05
Mostly asked as numerical value (81%); 81% need a numerical answer, 50% are easy and 0% hard.
06
The skill tested most is calculation (81%), then conceptual (6%).

Questions a shift, year by year

Out of the 25 Chemistry questions in a shift. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift.

Raw count: 2017: 0 in 1 shift · 2020: 3 in 12 shifts · 2021: 1 in 24 shifts · 2022: 4 in 24 shifts · 2023: 1 in 12 shifts · 2024: 6 in 18 shifts · 2025: 1 in 8 shifts · 2026: 0 in 9 shifts.

Up to 2023: 0.1; a shift, of 25
Since 2024: 0.1; 0.0
Usual gap: 1.0 yrs; between years asking it
Shifts with it: 16/108; 15% of analysed shifts

How it is asked

Difficulty, format and skill

Across all 16 questions on Faraday's Laws of Electrolysis since 2017.

Difficulty

QUESTIONS

Easy8 · 50%
Medium8 · 50%
Hard0 · 0%

Format

Numerical value · 13 Q81%
Single correct · 2 Q13%
Two statements · 1 Q6%

Skill tested

Calculation · 13 Q81%
Conceptual · 1 Q6%
Recall · 1 Q6%
Multi-step · 1 Q6%

Repeats

New idea, or one asked before?

Each column is a year. Blue questions tested an idea no earlier year had asked; navy ones went back to an idea from an earlier year. 2017 is the first year, so everything in it counts as new. Heights are question counts, and Lumi analysed 1 to 24 shifts a year, so compare the split inside a column rather than heights across years.

’17’20’21’22’23’24’25’26

Idea asked for the first time
Idea asked in an earlier year

Coverage of the topic

JEE Main has asked 9 of the 49 ideas in this topic. 36 have never been asked yet.

936

Asked directly9 · 18%
Touched inside another question4 · 8%
Never asked36 · 73%

Ideas come from Lumi’s JEE syllabus map. A never-asked idea is not a safe skip: across all of JEE Main, 22% of questions since 2024 tested an idea no earlier year had asked.

Drill down

Idea, year, question

Every idea JEE Main tested in this topic, with its eight years. Open one to read the questions.

ideaAskedShareYears’17’20’21’22’23’24’25’26

OpenRepeated4 · 25%25%3/82
- 31 Jan ’24 S1 · Q85
  One Faraday of electricity liberates $x\times10^{-1}$ gram atom of copper from copper sulphate. $x$ is _________.
  easyNumerical value
- 26 Jul ’22 S1 · Q87
  The amount of charge in F (Faraday) required to obtain one mole of iron from $\mathrm{Fe_3O_4}$ is ____________. (Nearest Integer)
  mediumNumerical valueAsked the year before
- 28 Jun ’22 S1 · Q87
  The quantity of electricity in Faraday needed to reduce 1 mol of $\mathrm{Cr_2O_7^{2-}}$ to $\mathrm{Cr^{3+}}$ is ________
  easyNumerical valueAsked the year before
- 26 Feb ’21 S1 · Q56
  Consider the following reaction $\mathrm{MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{+2} + 4H_2O}$ , $\mathrm{E^\circ} = 1.51$ V. The quantity of…
  easyNumerical valueNew idea
OpenRepeated3 · 19%19%3/8
OpenRepeated2 · 13%13%2/8
OpenRepeated2 · 13%13%2/8
Open1 · 6%6%1/8
Open1 · 6%6%1/8
Open1 · 6%6%1/8
Open1 · 6%6%1/8
Open1 · 6%6%1/8

Squares are the 8 years with analysed shifts, 2017 to 2026. A number is the questions that year when there is more than one; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. Share is of the level above.

Ideas

Every idea inside this topic

9 different ideas were tested; 4 came more than once.

Charge-Mole Relationship4×
moles liberated per faraday
Numerical value · 4 shifts · 4 numerical
Gas Evolution Volume3×
gas volume from electrolysis charge
Numerical value · 3 shifts · 3 numerical
Predicting Products2×
statement i/ii on electrolysis products
Single correct · 2 shifts
Faraday's First Law2×
mass deposited from current and time
Numerical value · 2 shifts · 2 numerical
Electrochemical Equivalent (Z) Calculation1×
definition of electrochemical equivalent
Single correct · 1 shift
Number of Deposited Atoms1×
atoms deposited from coating thickness
Numerical value · 1 shift · 1 numerical
Water Consumption Stoichiometry1×
charge to oxidise one mole of water
Numerical value · 1 shift · 1 numerical
Electroplating Thickness and Area1×
time for electroplating thickness
Numerical value · 1 shift · 1 numerical
Current Efficiency1×
current efficiency of electrolysis
Numerical value · 1 shift · 1 numerical

Idea	Times	Shifts	Format	Numerical
Charge-Mole Relationshipmoles liberated per faraday	4	4	Numerical valueCalculation	4
Gas Evolution Volumegas volume from electrolysis charge	3	3	Numerical valueCalculation	3
Predicting Productsstatement i/ii on electrolysis products	2	2	Single correctConceptual	–
Faraday's First Lawmass deposited from current and time	2	2	Numerical valueCalculation	2
Electrochemical Equivalent (Z) Calculationdefinition of electrochemical equivalent	1	1	Single correctRecall	–
Number of Deposited Atomsatoms deposited from coating thickness	1	1	Numerical valueCalculation	1
Water Consumption Stoichiometrycharge to oxidise one mole of water	1	1	Numerical valueCalculation	1
Electroplating Thickness and Areatime for electroplating thickness	1	1	Numerical valueCalculation	1
Current Efficiencycurrent efficiency of electrolysis	1	1	Numerical valueCalculation	1

Times and shifts count every analysed shift. Across JEE Main, 78% of questions since 2024 went back to an idea an earlier year had asked; the rest were new. All repeated ideas

Every question

Faraday's Laws of Electrolysis questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested. Open one for its options and the official answer.

Questions from the official JEE Main Paper 1 shifts published by NTA (CBSE for 2017). Questions NTA dropped are left out. Topic and idea tags, counts and notes are Lumi’s.

Key findings

Questions a shift, year by year

Difficulty, format and skill

Difficulty

Format

Skill tested

New idea, or one asked before?

Coverage of the topic

Idea, year, question

Every idea inside this topic

Faraday's Laws of Electrolysis questions, year by year

JEE Main 20251 question in 1 shift

JEE Main 20246 questions in 6 shifts

JEE Main 20231 question in 1 shift

JEE Main 20224 questions in 4 shifts

JEE Main 20211 question in 1 shift

JEE Main 20203 questions in 3 shifts

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