NCERT Solutions for Chapter: Environmental Chemistry, Exercise 1: Short Answer Type

Why does water covered with excessive algal growth become polluted?

A factory was started near a village. Suddenly villagers started feeling the presence of irritating vapours in the village and cases of headache, chest pain, cough, dryness of throat and breathing problems increased. Villagers blamed the emissions from the chimney of the factory for such problems. Explain what could have happened. Give chemical reactions for the support of your explanation.

Oxidation of sulphur dioxide into sulphur trioxide in the absence of a catalyst is a slow process but this oxidation occurs easily in the atmosphere. Explain how does this happen. Give chemical reactions for the conversion of ${\mathrm{SO}}_2$ into ${\mathrm{SO}}_3$.

From where does ozone come in the photochemical smog?

How is ozone produced in stratosphere?

Ozone is a gas heavier than air. Why does the ozone layer not settle down near the earth? 

Some time ago the formation of polar stratospheric clouds was reported over Antarctica. Why were these formed? What happens when such clouds break up by the warmth of sunlight?  

 A person was using water supplied by the Municipality. Due to a shortage of water, he started using underground water. He felt a laxative effect. What could be the cause?