Question

When chlorine reacts with cold and dilute solution of sodium hydroxide, the products obtained are:
A. $C{{l}^{-}}+Cl{{O}^{-}}$
B. $C{{l}^{-}}+Cl{{O}^{2-}}$
C. $C{{l}^{-}}+Cl{{O}^{3-}}$
D. $C{{l}^{-}}+Cl{{O}^{4-}}$

Answer 1

Hint: Chlorine gas with cold and dilute sodium hydroxide to produce sodium hypochlorite. Sodium hypochlorite is a bleaching agent.

Complete Step by Step Answer:
Chlorine is a halogen element. Chlorine gas on reaction with cold and dilute sodium hydroxide produces sodium hypochlorite which acts as a bleaching agent along with sodium chloride and water.

The reaction can be given as follows:
$2NaOH+C{{l}_{2}}\to NaOCl+NaCl+{{H}_{2}}O$

In this reaction one mole of Chlorine gas in reaction with two moles of cold and dilute sodium hydroxide produces one mole of sodium hypochlorite which acts as a bleaching agent along with one mole of sodium chloride and one mole of water. Thus $C{{l}^{-}}+Cl{{O}^{-}}$are produced.
Thus the correct option is A.

Additional Information: Chlorine gas on reaction with hot and concentrate sodium hydroxide produces sodium chlorate which does not act as a bleaching agent along with sodium chloride and water. The reaction can be given as follows:
$6NaOH+3C{{l}_{2}}\to Na{{O}_{3}}Cl+5NaCl+3{{H}_{2}}O$
In this reaction three moles of Chlorine gas in reaction with six moles of hot and concentrated sodium hydroxide produces one mole of sodium chlorate which does not act as a bleaching agent along with five moles of sodium chloride and three moles of water.

Note: Sodium hypochlorite that is produced in this reaction is highly used as a bleaching agent, sterilisation and preparation of antiseptic. The nascent oxygen prepared by chlorine in presence of moisture helps in the bleaching.