JEE Main 2019 — Electrochemistry Question with Solution
From: JEE Main 2019 (Online) 8th April Evening Slot
Question
Calculate the standard cell potential in (V) of the
cell in which following reaction takes place :
Fe2+(aq) + Ag+(aq) Fe3+(aq) + Ag (s)
Given that
Fe2+(aq) + Ag+(aq) Fe3+(aq) + Ag (s)
Given that
Choose an option
Show full solutionCorrect option: A
Correct answer
Ax + 2y - 3z
Step-by-step explanation
Standard emf,
..............(1)
Given
Fe2+ + 2e- Fe ..........(2)
= y and = -2Fy
Also given
Fe3+ + 3e- Fe .........(3)
= z and = -3Fz
Performing (2) - (1), we get
Fe3+ + e- Fe2+
= -3Fz + 2Fy
-(1)F = -3Fz + 2Fy
= 3z - 2y
From Equation (1),
= x - (3z - 2y) = x + 2y - 3z
..............(1)
Given
Fe2+ + 2e- Fe ..........(2)
= y and = -2Fy
Also given
Fe3+ + 3e- Fe .........(3)
= z and = -3Fz
Performing (2) - (1), we get
Fe3+ + e- Fe2+
= -3Fz + 2Fy
-(1)F = -3Fz + 2Fy
= 3z - 2y
From Equation (1),
= x - (3z - 2y) = x + 2y - 3z
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This is a previous-year question from JEE Main 2019, 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.