Question

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> State why an aqueous solution of ammonia turns red litmus to blue. (1 mark)

Answer 1

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Ammonia on dissolving in water furnishes ammonium ions and hydroxyl ions.
${\mathrm{NH}}_3\left(\mathrm{aq}\right)+H_{2}O\left(l\right)\to {\mathrm{NH}}_4^{+}\left(\mathrm{aq}\right)+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$
(0.5 mark)

The presence of ${\mathrm{OH}}^{-}$ ion turns red litmus to blue.
(0.5 mark)