The gas A is used by most of the animals to obtain energy from food by the process of respiration. When A is acted upon by radiation X, it gets converted into another gas B which is an allotrope of A but poisonous when inhaled. B forms a kind of layer C in the upper atmosphere which absorbs radiations X coming from a source Y and prevent them from reaching the earth. Some chemicals Z released from the various devices on the earth are destroying the layer C slowly. In fact, a hole has already been formed in layer C over the aea D of the earth.
(a) What are gases (i) A, and (ii) B? Write their molecular formulae.
(b) Name the layer C.
(c) What are (i) X, (ii) Y, (iii) Z ?
(d) Name the area D.
(e) Name any two human ailments which may be caused by X.

Answer

(a) (i) Oxygen, `O_(2)` (ii) Ozone, `O_(3)` (b) Ozone layer (c) (i) Ultraviolet radiations (ii) Sun (iii) Chlorofulorocarbons (CFCs) (d) Antarctica (e) Skin cancer ; Cataract