The correct statement about \(\mathrm{Cr}^{2+}\) and \(\mathrm{Mn}^{3+}\) among the following is (Given,…

The correct statement about \(\mathrm{Cr}^{2+}\) and \(\mathrm{Mn}^{3+}\) among the following is (Given, atomic numbers of \(\mathrm{Cr}=24\) and \(\mathrm{Mn}=25\) )
  1. \(\mathrm{Cr}^{2+}\) is an oxidising agent
  2. \(\mathrm{Mn}^{3+}\) is a reducing agent
  3. Both \(\mathrm{Cr}^{2+}\) and \(\mathrm{Mn}^{3+}\) exhibit \(d^4\) outer electronic configuration
  4. When \(\mathrm{Cr}^{2+}\) is used as reducing agent, it attains \(d^5\) configuration

Solution

\(\begin{aligned} \mathrm{Cr}^{2+} & \Rightarrow[\mathrm{Ar}] 3 d^4, E_{\mathrm{Cr}^{3+} / \mathrm{Cr}^{2+}}^{\circ}=-0.41 \mathrm{~V} \\ \mathrm{Mn}^{3+} & \Rightarrow[\mathrm{Ar}] 3 d^4, E_{\mathrm{Mn}^{3+} / \mathrm{Mn}^{2+}}^0=+1.51 \mathrm{~V} \end{aligned}\) So, reducing power \(\mathrm{Cr}^{2+} > \mathrm{Mn}^{2+}\) *

Asked in: JEE-TOPICTESTS-CHEMISTRY

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