P. Bahadur Solutions for Chapter: Metals and Non-metals, Exercise 3: Exercise 7

${\mathrm{F}}_2\mathrm{O}$ is fluorine oxide.

${\mathrm{CrO}}_3$ is an acidic oxide.

${\mathrm{Al}}_2{\mathrm{O}}_3, {\mathrm{SnO}}_2$ and $\mathrm{ZnO}$ are amphoteric oxides.

On dissolution of ${\mathrm{SO}}_2$ in water, there exists an equilibrium:
${\mathrm{SO}}_2+{\mathrm{H}}_2\mathrm{O}\iff {\mathrm{H}}_2{\mathrm{SO}}_3$

Five metals $\mathrm{Cu}, \mathrm{Hg}, \mathrm{Ag}, \mathrm{Au}$ and $\mathrm{Pt}$ are placed below hydrogen in activity series.

Sulphur is used in the vulcanisation of rubber.

Metal hydrides on dissolution in water produce hydrogen gas.

Aqua regia($3 \mathrm{part} \mathrm{HCl} + 1 \mathrm{Part} {\mathrm{HNO}}_3$) is also called royal water.