Question

Extent of hydration of $N{a}^{+},M{g}^{2+},A{l}^{3+}$ is in order

• A. $N{a}^{+}<A{l}^{3+}<M{g}^{2+}$
• B. $N{a}^{+}<M{g}^{2+}<A{l}^{3+}$
• C. $A{l}^{3+}<M{g}^{2+}<N{a}^{+}$
• D. Equal

Answer 1

Answer: (B)

$N{a}^{+},M{g}^{2+}$ and $A{l}^{3+}$ are isoelectronic
Size $N{a}^{+}>M{g}^{2+}>A{l}^{3+}$
Charge $+1+2+3$
Smaller the size of cation,
Larger the charge,
Greater the hydration
Thus, $N{a}^{+}<M{g}^{2+}<A{l}^{3+}$