. Study the following statements about ozone
(a) It is essential for breathing of living organisms.
(b) It is used to disinfect water.
(c) It absorbs ultraviolet rays.
(d) Its proportion in air is about 3%.
Which of these statements are correct?
(i) (a), (b) and (c)
(ii) (b) and (c)
(iii) (a) and (d)
(iv) All four
Correct Answer : (ii) (b) and (c)
Solution: Ozone is used to disinfect water during wastewater treatment. Ozone is an unstable gas that destroys bacteria and virus.
It also absorbs ultraviolet rays coming from the sun.