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The correct statement (s) about Cr²⁺ and Mn³⁺ is/are [atomic number of Cr=24 and Mn=25]

$Cr^{2+}$ is a reducing agent

$Mn^{3+}$ is an oxidising agent

C) both

$Cr^{2+}$ and

$Mn^{3+}$ exhibit

$d^{4}$ electronic configuration

D) when

$Cr^{2+}$ is used as a reducing agent, the chromium ion attains

$d^{5}$ electronic configuration

Answer:

Option A,B,C

Explanation:

(a) In an aqueous solution Cr²⁺ (3d⁴) acts as a reducing agent, oxidising itself to Cr³⁺ (3d³) that gives a completely half-field t_2g level in the octahedral ligand field of H₂O.

(b) Mn³⁺ (3d⁴) is an oxidising agent as it is reduced to Mn²⁺ (3d⁵) , a completely half-filled stable configuration.

(d) $3d^{4}Cr^{2+}(aq)$ $\underrightarrow{R.A}$ $Cr^{3+}(aq)+\overline{e}$

hence (d) is wrong statement.

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