The main oxides formed on combustion of Li,Na and K in excess of air respectively are

Options

A. `Li_(2)O_(2), Na_(2)O_(2) and KO_(2)`
B. `Li_(2)O, Na_(2)O_(2) and KO_(2)`
C. `Li_(2)O, Na_(2)O and KO_(2)`
D. `LiO_(2), Na_(2)O_(2) and K_(2)O`

Answer

A

Explanation

The solubility of sulphates of alkaline earth metals decreases as we move down the group from Be to Ba due to the reason that ionic size increases down the 5. group. The lattice energy remains constant because sulphate ion is so large, so that small change in cationic sizes do not make any difference. Thus the order will be `Mg> Ca> Sr > Ba`