The correct statement(s) about $\mathrm{Cr}^{2+}$ and $\mathrm{Mn}^{3+}$ is(are) [Atomic numbers of

Question

The correct statement(s) about $\mathrm{Cr}^{2+}$ and $\mathrm{Mn}^{3+}$ is(are) [Atomic numbers of $\mathrm{Cr}=24$ and $\mathrm{Mn}=25$ ]\

Professor PC Thomas Classes · Answer

(a,b, c) : (a) $\mathrm{Cr}^{2+}$ is a reducing agent, it gets oxidised to $\mathrm{Cr}^{3+}\left(3 d^{3}\right.$ or $t_{2 g}^{3}$, stable half-filled configuration).\ (b)$\mathrm{Mn}^{3+}$ is an oxidizing agent, it gets reduced to $\mathrm{Mn}^{2+}\left(3 d^{5}\right.$, most stable, halffilled configuration).\(c)$\operatorname{Cr}(24): 3 d^{4} 4 s^{2}$; $$ \operatorname{Mn}(25): 3 d^{5} 4 s^{2} \ \mathrm{Cr}^{2+}: 3 d^{4}\  \mathrm{Mn}^{3+}: 3 d^{4} $$ Both $\mathrm{Cr}^{2+}$ and $\mathrm{Mn}^{3+}$ exhibit $d^{4}$ electronic configuration.\(d)When $\mathrm{Cr}^{2+}$ is used as a reducing agent, the chromium ion attains $d^{3}$ electronic configuration.\