Question

Identify the gas evolved and give the chemical test in each of the following:

Dilute Hydrochloric acid reacts with Sodium sulphate.

Answer 1

• Under NTP, no reaction will occur.
• $$\begin{gathered} {\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{s}\right)+2\mathrm{HCl}(dil.)\to {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+2\mathrm{NaCl}\left(\mathrm{s}\right) \\ \mathrm{Sodium}\mathrm{Hydrochloric}\mathrm{Sulphuric}\mathrm{Sodium} \\ \mathrm{sulphate}\mathrm{acid}\mathrm{acid}\mathrm{chloride} \end{gathered}$$, this reaction will not take place because Sulphuric acid is stronger than Hydrochloric acid.
• the Following reaction will take place instead of the above reaction$$\begin{gathered} {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+2\mathrm{NaCl}\left(\mathrm{s}\right)\stackrel{>200°\mathrm{C}}{\to }{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{s}\right)+2\mathrm{HCl}\left(\mathrm{g}\right)\uparrow \\ \mathrm{Sulphuric}\mathrm{Sodium}\mathrm{Sodium}\mathrm{Hydrochloric} \\ \mathrm{acid}\mathrm{chloride}\mathrm{sulphate}\mathrm{acid} \end{gathered}$$.
• Hydrogen chloride gas will evolve when Sulphuric acid reacts with Sodium chloride.