Question

When $C{l}_2$ gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from :

• A. zero to -1 and zero to + 5
• B. zero to -1 and zero to +3
• C. zero to +1 and zero to -3
• D. zero to +1 and zero to -5

Answer 1

Answer: (A)

Chlorine reacts with hot and concentrated NaOH solution and dispropositionates into chloride $(C{l}^{-})$ and chlorate $(CI{O}_3^{-})$ ions.
In the reaction oxidation state of chlorine changes from 0 to -1 and 0 to + 5.
In dispropositionation, the same element undergoes oxidation as well as reduction simultaneously.