Question

Sometimes, a sticky mass of ____ is formed during the laboratory preparation of hydrochloric acid.

Answer 1

During the laboratory preparation of Hydrochloric acid $\left(\mathrm{HCl}\right)$, a sticky mass of Sodium sulfate $\left({\mathrm{Na}}_2{\mathrm{SO}}_4\right)$ forms.
The reaction is given below:
$\mathbf{NaCl}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}{\mathbf{H}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{}\mathbf{\to }\mathbf{}{\mathbf{Na}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{}\mathbf{+}\mathbf{}\mathbf{HCl}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}$

Sometimes, a sticky mass of Sodium sulfate$\left({\mathrm{Na}}_2{\mathrm{SO}}_4\right)$ is formed during the laboratory preparation of Hydrochloric acid$\left(\mathbf{HCl}\right)$.