Question

Sodium thiosulphate could be synthesized by

• A. boiling aqueous NaOH with Sulphur
• B. heating a solution of a Sodium sulphite with finely powdered S in an alkaline medium
• C. Spring’s reaction
• D. All of the above

Answer 1

The correct option is D

All of the above

$N{a}_2{S}_2{O}_3$ could be prepared by heating a solution of a Sodium sulphite with finely powdered S in an alkaline medium at 330 K:

$N{a}_{2}S{O}_3\left(aq\right)+S\left(s\right)\to N{a}_2{S}_2{O}_3\left(aq\right)$

When aqueous NaOH is boiled with Sulphur:

$6NaOH\left(aq\right)+4S\left(s\right)\to N{a}_2{S}_2{O}_3\left(aq\right)+2N{a}_{2}S\left(aq\right)+3H_{2}O\left(I\right)$

Spring’s reaction: When a measured amount of $I_2$ is added to a mixture of Sodium Sulphide and Sodium Sulphite, we obtain hypo. Sodium thiosulphate pentahydrate, commonly called “hypo,” can easily be prepared by boiling sulphur in a solution of sodium sulphite:

$N{a}_{2}S{O}_3+N{a}_{2}S+I_2\to N{a}_2{S}_2{O}_3$