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JEE Main 20241 FebruaryEvening Shift
Exam
JEE Main
Year
2024
Date
1 February
Shift
Evening Shift
Subject
Chemistry
Chapter
d and f Block Elements

JEE Main 2024 · 1 February · Evening Shift · Chemistry · d and f Block Elements

Given below are two statements : one is labelled as Assertion (A)...

Given below are two statements : one is labelled as Assertion (A) andtheotherislabelledasReason(R).\left(A\right) and the other is labelled as Reason \left(R\right) .

Assertion \left(A\right):Inaqueoussolutions: In aqueous solutions{Cr}^{2 +}isreducingwhileis reducing while{Mn}^{3 +}isoxidisinginnature.</p><p>Reason(R):is oxidising in nature.</p><p>Reason \left(R\right): Extra stability to half filled electronic configuration is observed than incompletely filled electronic configuration.

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

Options

  1. ABoth (A)\left(A\right) and (R)\left(R\right) are true and (R)\left(R\right) is the correct explanation of (A)\left(A\right)
  2. BBoth (A)\left(A\right) and (R)\left(R\right) are true but (R)\left(R\right) is not the correct explanation of (A)\left(A\right)
  3. C(A)\left(A\right) is false but (R)\left(R\right) is true
  4. D(A)\left(A\right) is true but (R)\left(R\right) is false

Correct answer

A. Both (A)\left(A\right) and (R)\left(R\right) are true and (R)\left(R\right) is the correct explanation of (A)\left(A\right)

Step-by-step solution

A reducing agent, or reductant, loses electrons and is oxidized in a chemical reaction. A reducing agent is typically in one of its lower possible oxidation states, and is known as the electron donor.

Cr2+{Cr}^{2 +} is reducing as it configuration changes from d4{d}^{4} to d3{d}^{3} due to formation of Cr3+,{Cr}^{3 +}, which has half filled t2g{t}_{2g} level, on other hand, the change Mn3+{Mn}^{3 +} to Mn2+{Mn}^{2 +} result half filled d5{d}^{5}configuration which has extra stability.

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