Question

Comment on each of the following:

(i) the mobilities of alkali metal ions in aqueous solution are:

Li⁺ < Na⁺ < K⁺ < Rb⁺ < Cs⁺

(ii) Lithium is the only metal to form nitride directly.

(iii) BaO is soluble but BaSO₄ is insoluble in water.

Answer 1

(i) Small size ∝ Hydrations energy ∝ \(\frac{1}{ionic\,mobility}\)

(ii) Lithium on account of its small size, shows anomalous behavior.

(iii) BaO is soluble but BaSO₄ is insoluble on account of higher lattice energy of BaSO₄ than its hydration energy.