Question

_______ is a greenish yellow gas having an irritating choking and unpleasant odour.
A. Fluorine
B. Bromine
C. Chlorine
D. Hydrogen sulphide

Answer 1

Hint: This greenish yellow gas is used to treat drinking water and swimming pool water and is also used in the preparation of bleaching powder.

Complete step by step solution:
We can easily solve this question just by inspecting each option given above.
Starting from option A which is fluorine. We know that fluorine gas is pale yellow in color. It is highly corrosive, flammable gas with a pungent odour. So, option A is not correct.
Now coming to option B which is bromine. We know that bromine is a liquid at room temperature. It is reddish brown in color. Also, it has pungent odour and is irritating to skin, eyes and also to the respiratory system. So, option B is also not correct.
Now, we will look at option C which is chlorine. We know that chlorine is a greenish yellow gas and is not flammable. It is recognized by its pungent and irritating odour.
So, we can say that option C is the correct option.
Now coming to the last option which is hydrogen sulphide. We know that hydrogen sulphide is a colorless gas. It is flammable and is recognized by its odour of rotten eggs.
So, option D is also not correct.
Therefore, from above we can say that option C is the correct option.

Note: It should be remembered that chlorine gas is used in the preparation of chloroform. Also, it should be noted that chlorine has the highest electron affinity of all elements known.