Question

What happens when dilute $\mathrm{HCl}$ is added to ${\mathrm{Na}}_2{\mathrm{CO}}_3$ placed in a test tube?

• A. An explosion takes place.
• B. Brisk effervescence takes place.
• C. Gas with a pungent smell is evolved.
• D. No chemical reaction takes place.

Answer 1

The correct option is B

Brisk effervescence takes place.

Explanation for the correct option:

1. When dilute $\mathrm{HCl}$(Hydrochloric acid) is added to ${\mathrm{Na}}_2{\mathrm{CO}}_3$ (Sodium carbonate) placed in a test tube, Sodium chloride ($\mathrm{NaCl}$), Water (${\mathrm{H}}_2\mathrm{O}$) and Carbon dioxide (${\mathrm{CO}}_2$) gas are formed.
2. The reaction can be given as: $$\begin{gathered} {\mathrm{Na}}_2{\mathrm{CO}}_3\left(\mathrm{s}\right)+2\mathrm{HCl}\left(\mathrm{aq}\right)\to 2\mathrm{NaCl}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)\uparrow \\ (\mathrm{Sodium}\mathrm{carbonate})(\mathrm{Hydrochloric}\mathrm{acid})(\mathrm{Sodium}\mathrm{chloride})\left(\mathrm{Water}\right)(\mathrm{Carbon}\mathrm{dioxide}) \end{gathered}$$.
3. A brisk effervescence is seen in the release of Carbon dioxide gas.

Explanation for the incorrect options:

Option (A) is incorrect because though the reaction is exothermic, but it is not explosive.

Option (C) is incorrect because carbon dioxide that is evolved is odorless and it does not have any pungent odor.

Option (D) is incorrect because here a chemical reaction is taking place where a carbonate is getting decomposed by the application of an acid to give salt, water and carbon dioxide.

Hence, the option (B) is correct. i.e., Brisk effervescence takes place, when dilute $\mathrm{HCl}$ is added to ${\mathrm{Na}}_2{\mathrm{CO}}_3$ placed in a test tube.