Explanation

(b)
(i) The alkali metal superoxides contain $O_{2}^{-}$ ion, which has an unpaired electron, hence they are paramagnetic in nature.
(ii) The basic character of alkali metal hydroxides increases on moving down the group.
(iii) The conductivity of alkali metal chlorides in their aqueous solution increases on moving down the group because in aqueous solution alkali metal chlorides ionize to give alkali metal ions. On moving down the group the size of alkali metal ion increases, thus degree of hydration decreases, due to this reason their conductivity in aqueous solution increases on moving down the group.
(iv) DIAGRAM
$CO_{3}^{2 -} + 2H_{2}O\ \rightarrow H_{2}CO_{3} + 2OH^{-}$
Thus, basic nature of carbonates in aqueous solution is due to anionic hydrolysis.