Solved Examples on Environmental Chemistry:

Question.1 Why does rain water have a pH of about 5 – 6?

Solution:  Normally rain has a pH of about 5 – 6 due to dissolution of  of the atmosphere into it.

Question.2  Explain giving reasons. ‘The presence of CO reduces the amount of haemoglobin available in the blood for carrying oxygen to the body cells’.

Solution: CO combines with haemoglobin of the red blood corpuscles about 300 times more easily than oxygen to form carboxy haemoglobin reversibly as follows:

Thus it is not able to combine with oxygen to form oxyhaemoglobin and transport of oxygen to different body cell cannot take place.

Question.3 Why is acid rain considered as a threat to ‘Taj Mahal’?

Solution: Taj Mahal is made of marble. The acid rain contains which attacks the marble  thereby pitting it, decolourising it and making it lustreless.

Question. 4 The acid rain does not contain 

(A)  Sulphuric acid            (B)   Nitric acid

(C)  Sulphurous acid          (D)  Acetic acid

Solution: Nitrogen oxides & acidic soots. Sulphurdioxide & nitrogen dioxide interact with water vapours in presence of sunlight to form sulphuric acid & nitric acid units. 

Acid rain contains sulphuric acid, nitric acid, sulphurous acid but does not contain acetic acid.

Hence, the correct option is D.