Account for the following:
On addition of ozone gas to KI solution, violet vapours are obtained.

Write balance equations for the following reaction:
$\mathrm{Cu}+\mathrm{conc}. {\mathrm{H}}_2{\mathrm{SO}}_4 \to$

Write balance equation for the following reaction:
${\mathrm{SF}}_4+{\mathrm{H}}_2\mathrm{O} \underset{\mathrm{catalyst}}{\to }$

Write balance equation for the following reaction:
${\mathrm{H}}_2\mathrm{S} + {\mathrm{SO}}_2 \to$

Write balance equation for the following reaction:
$\mathrm{Te}\left(\mathrm{s}\right) + {\mathrm{Cl}}_2\left(\mathrm{g}\right) \to$

589. SOCl₂ can act as a weak Lewis acid as well as a weak Lewis base. Explain.