Question

(a) Name two compounds that are covalent when taken pure but produce ions when dissolved in water.

(b) For each compound mentioned above, give the formulae of ions formed in aqueous solutions.

Answer 1

The two covalent compounds are HCl and NH3. They are covalent in nature when taken pure but produces ion when dissolve in water.
$HCl+H_{2}O\rightleftharpoons H_3{O}^{+}+C{l}^{-}$
$N{H}_3+H_{2}O\rightleftharpoons N{H}_4^{+}+O{H}^{-}$

b) - They neutralise each other, if the quantities are right you end up with a neutral ionic solution of ammonium chloride. If one or the other is in excess then you will have a solution of ammonium chloride with excess hydrochloric acid or excess ammonia.

$N{H}_3+HCl\rightleftharpoons N{H}_4^{+}+C{l}^{-}$

The fumes from ammonia solution and hydrochloric acid to produce $N{H}_4^{+}andC{l}^{-}$ ions