Given below are two statements: Statement I: The $E^{\circ}$ value for $\ce{Ce^{4+}/Ce^{3+}}$ is +1.74 V Statement II: Ce is more stable in $\ce{Ce^{4+}}$ state than $\ce{Ce^{3+}}$ state In the light of the above statements, choose the most appropriate answer from the options given below:

(A) Statement I is incorrect but statement II is correct

(C) Both statement I and statement II are correct

(D) Both statement I and statement II are incorrect

JEE Main · 2021 · 16 Mar 2021 · Shift 1 · d and f Block Elements

Given below are two statements:
Statement I: The

E^{\circ}

value for

Ce X^{4 +} / Ce X^{3 +}

is +1.74 V
Statement II: Ce is more stable in

Ce X^{4 +}

state than

Ce X^{3 +}

state
In the light of the above statements, choose the most appropriate answer from the options given below:

(A)Statement I is incorrect but statement II is correct
(B)Statement I is correct but statement II is incorrect✓ Correct
(C)Both statement I and statement II are correct
(D)Both statement I and statement II are incorrect

Answer: (B)

Solution

The standard reduction potential of the

C e^{4 +} /C e^{3 +}

couple is

+ 1.74

V. A value this large and positive means

C e^{4 +}

accepts an electron readily, which is why ceric sulphate serves as an oxidising titrant in volumetric analysis. Statement I is correct.
A species that is so strong an oxidising agent is the less stable member of the pair. Cerium is in fact more stable as

C e^{3 +}

, the

+ 3

state characteristic of the lanthanoids, and reverts to it whenever a reducing agent is available. Statement II is incorrect.
Statement I is correct but Statement II is incorrect.

JEE Main · 2021 · 16 Mar 2021 · Shift 1 · Single correct option

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JEE Main · 2021 · 16 Mar 2021 · Shift 1 · d and f Block Elements

Solution

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