For the preparation of sodium thiouslphyate by "Spring's reaction', the reactants used are

Options

A. `Na_(2)S+Na_(2)SO_(3)+CI_(2)`
B. `Na_(2)S+SO_(2)`
C. `Na_(2)S+Na_(2)SO_(3)+I_(2)`
D. `Na_(2)SO_(3)+S`

Answer

C

Explanation

Spring's reaction for preparation of sodium thiousulphate.
`Na_(2)S+Na_(2)SO_(3)+I_(2)rarr Na_(2)S_(2)O_(3)+2NaI`
The resulting solution is concentrated and allowed to crystallise, when crysals of `Na_(2)S_(2)O_(3).5H_(2)O` being less soluble, separates out first.