Question

(c) Write balanced equations for the following reactions:
(i) dissolving sulphur trioxide in water.
(ii) Aluminium powder is warmed with hot and concentrated caustic soda solution.
(iii) Concentrated nitric acid is added to copper turnings kept in a beaker.
(iv) Red lead (trilead tetroxide) is warmed with concentrated hydrochloric acid.

Answer 1

The balanced chemical equations for the given reactions are as follows:

(i) Dissolution of sulphur trioxide in water:

${\mathrm{SO}}_3+{\mathrm{H}}_2\mathrm{O}\to {\mathrm{H}}_2{\mathrm{SO}}_4$

(ii) Aluminium powder warmed with hot and concentrated caustic soda solution:

$2\mathrm{Al}+2\mathrm{NaOH}+6{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{Na}\left[\mathrm{Al}{\left(\mathrm{OH}\right)}_4\right]+3{\mathrm{H}}_2$

(iii) Concentrated nitric acid added to copper turnings kept in a beaker:

$\mathrm{Cu}+4{\mathrm{HNO}}_3\to \mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2+2{\mathrm{H}}_2\mathrm{O}+2{\mathrm{NO}}_2$

(iv) Red lead (trilead tetroxide) warmed with concentrated hydrochloric acid:

${\mathrm{Pb}}_3{\mathrm{O}}_4+8\mathrm{HCl}\to 3{\mathrm{PbCl}}_2+4{\mathrm{H}}_2\mathrm{O}+{\mathrm{Cl}}_2\uparrow$