When `CI_(2)` gas reacts with hot and concentrated sodium hydroxide solution ,the oxidation number of chlorine changes from:

Options

A. Zero to `+1` and Zero to `-5`
B. Zero to `-1` and Zero to `+5`
C. Zero to `-1` and Zero to `+3`
D. Zero to `+1` and Zero to `-3`

Answer

2

Explanation

Chlorine reacts with hot and conc. Sodium hydroxide solution to yield sodium chloride sodium chlorate:
`underset("O.N. of Cl is 0")(3Cl_(2)(g))+6Na^(+)OH^(-) (aq.) rarr underset("O.N. of Cl is -1")(5Na^(+)Cl^(-) (aq.))+underset("O.N. of Cl is +5")(Na^(+) ClO_(3)^(-)(aq.))+3H_(2)O(l)`
However, sodium chloride and sodium hypochlorite are formed when chlorine gas reacts with cold and dilute sodium hydroxide solution:
`underset("O.N. of Cl is 0")(Cl_(2)(g))+2Na^(+)OH^(-)(aq.) rarr underset("O.N. of Cl is -1")(Na^(+)Cl^(-)(aq.))+underset("O.N. of Cl is +1")(Na^(+) ClO^(-) (aq.))+H_(2)O(l)`