Chemistry - CHEMICAL BONDING Question with Solution | TestHub

(a) is correct: Solubility of alkali metal hydroxides increases down the group because lattice energy decreases more rapidly than hydration energy as cation size increases.

(b) is incorrect: Due to the inert pair effect, the stability of the $+1$ oxidation state increases down Group 13 ($G{a}^{+}<I{n}^{+}<T{l}^{+}$).

(c) is incorrect: Thermal stability of alkali metal carbonates increases down the group as the polarizing power of the cation decreases.

(d) is incorrect: Polarizability increases with larger ionic size and higher negative charge ($S^{2-}>O^{2-}>F^{-}$).