Fill in the blanks:

(a) …………… is the most abundant inert gas present in air.

(b) Oxides of sulphur and nitrogen combine with rain water to form …………… and …………… which cause …………… .

(c) …………… and …………… are the most common air pollutants.

(d) …………… discovered the oxygen gas.

(e) Oxygen occupies about …………… of air by volume.

(a) Argon

(b) sulphurous acid, sulphuric acid, nitrous acid, nitric acid, acid rain

(c) oxides of carbon, dust

(d) Joseph Priestly

(e) 21%