Identify the correct statements from the following :
i. In the presence of UV light , `CF_(2)Cl_(2)(g)` gives chlorine free radicals which will react with `O_(3)` (g) to form `O_(2)` (g).
ii. Drinking water with 10 ppm fluoride is better than drinking water with 1 ppm fluoride.
iii. The maximum permissible concentration of lead in drinking water is 50 ppb.

Options

A. i,ii,iii
B. i,ii only
C. ii,iii only
D. i,iii only

Answer

D

Explanation

Statement (i) and (iii) are correct statements whereas statement (ii) is incorrect.
Its correct explanation is as follows :
The drinking water with 1ppm fluoride is better than 10 ppm fluoride.
The EPA has set maximum allowable concentration of fluorine in water at 2 ppm to prevent enamel fluorosis and 4 ppm to prevent skeletal fluorosis.