Question

$E^{\circ }$ values for the couples $C{r}^{3+}/C{r}^{2+}$ & $M{n}^{3+}/M{n}^{2+}$ are $-0.41$ & $+1.51V$ respectively. Considering these values select the correct option:

• A. $C{r}^{2+}$ acts as a reducing agent and $M{n}^{3+}$ acts as an oxidising agent in their aqueous solutions
• B. $C{r}_{\text{(aq) }}^{2+}$ is more stable than $C{r}_{(aq)}^{3+}$
• C. $M{n}_{(aq)}^{3+}$ is more stable than $M{n}_{(aq)}^{2+}$
• D. None of these

Answer 1

Answer: (A)

$C{r}^{2+}$ acts as reducing agent because it is itself oxidised to $C{r}^{3+}$ giving it $t_{eg}{}^3$ configuration, whereas $M{n}^{3+}$ acts as oxidising agent giving it $3d^5$ configuration