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JEE Main 2023 — Electrochemistry Question with Solution

JEE Main 2023 (24 Jan Shift 1)

Question

At 298 K, a 1 litre solution containing 10 mmol of Cr2O72- and 100mmol of Cr3+ shows a pH of 3.0.

Given : Cr2O7→2-Cr3+;E0=1.330 V and 2.303RTF=0.059 V

The potential for the half cell reaction is x×10-3 V . The value of x is _____ .

Enter your answer

Show full solutionCorrect answer: 917
Correct answer
917

Step-by-step explanation

The balanced half-reaction can be written as follows,

Cr2O72-+14H++6e-→2Cr3++7H2O

Using Nernst equation

Ecell=Ecello-0.059nlogproductsreactants

For the above reaction, number of electrons involved n = 6.

E=1.33-0.0596log0.1210-210-314

E=1.33-0.0596×42=0.917

E=917×10-3

x=917.

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About this question

This is a previous-year question from JEE Main 2023, covering the Electrochemistry chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.