Question

chlorine is used for the removal of unwanted substances in water by ----

a. filtration

b. reduction

c. substitution

d. oxidation

clear my choice

Explanation:

Chlorine is a strong oxidizing agent. It oxidizes unwanted substances in water to remove them. Filtration is a physical separation method, reduction is the gain of electrons, and substitution is a reaction type not related to chlorine's function in water treatment here.

Answer:

D. oxidation