Question

Give reasons :

(a) $E^{\circ }$ value for $M{n}^{3+}/M{n}^{2+}$ couple is much more positive than that for $F{e}^{3+}/F{e}^{2+}.$

(b) Iron has higher enthalpy of atomization than that of copper.

(c) $S{c}^{3+}$ is colourless in aqueous solution whereas $T{i}^{3+}$ is coloured.

Answer 1

(a) $E^{\circ }$ value for $M{n}^{3+}/M{n}^{2+}$ couple is much more positive than that for $F{e}^{3+}/F{e}^{2+}$ due to stable configuration of $M{n}^{2+}\left(d^5\right)$ ion

(b) Iron has higher enthalpy of atomization than that of copper due to higher number of unpaired electrons in iron.

(c) $S{c}^{3+}$ is colourless in aqueous solution whereas $T{i}^{3+}$ is coloured due to the absence of unpaired d-electrons in $S{c}^{3+}$. $T{i}^{3+}$ has one unpaired electron.