Question

Write the balanced chemical equation for the following reaction.

Dilute Hydrochloric acid is added to Sodium thiosulfate solution.

Answer 1

Properties of Hydrochloric acid:

Action of Dilute Hydrochloric acid on Sodium thiosulfate: Dil.$\mathrm{HCl}$ reacts with Sodium thiosulfate solution$\left({\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3\right)$ and produces Sulphur dioxide$\left({\mathrm{SO}}_2\right)$ and yellow Sulphur is precipitated.

${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3\left(\mathrm{aq}\right)+2\mathrm{HCl}\left(\mathrm{aq}\right)\to 2\mathrm{NaCl}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+{\mathrm{SO}}_2\left(\mathrm{g}\right)+\mathrm{S}\left(\mathrm{s}\right)$

So the reaction of Sodium thiosulfate, Dil.$\mathrm{HCl}$ gives Sulphur dioxide$\left({\mathrm{SO}}_2\right)$ and yellow Sulphur.