Question

When Sodium carbonate is added to a test tube which dilute hydrochloric acid, a gas is evolved. The gas evolved is:

• A. hydrogen and it turns lime water into milky
• B. carbon dioxide and it smells like burning sulphur
• C. carbon dioxide and it turns lime water into milky
• D. hydrogen and it burn with a pop sound

Answer 1

The correct option is C

carbon dioxide and it turns lime water into milky

The explanation for the correct option:

Option C is the correct option.

1. When sodium carbonate is added to a test with dilute hydrochloric acid, the following reaction takes place:
2. $\underset{\left(\mathrm{Sodium}\mathrm{carbonate}\right)}{{\mathrm{Na}}_2{\mathrm{CO}}_3\left(\mathrm{s}\right)}+\underset{\left(\mathrm{Hydrochloric}\mathrm{acid}\right)}{2\mathrm{HCl}\left(\mathrm{l}\right)}\to \underset{\left(\mathrm{Sodium}\mathrm{chloride}\right)}{2\mathrm{NaCl}\left(\mathrm{aq}\right)}+\underset{\left(\mathrm{Carbon}\mathrm{dioxide}\mathrm{gas}\right)}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\left(\mathrm{Water}\right)}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$
3. Sodium carbonate + Hydrochloric acid $\to$Sodium chloride + water
4. From the above reaction, it is confirmed that carbon dioxide is released when sodium carbonate reacts with hydrochloric acid.
5. And Carbon dioxide has the characteristic property to convert lime water into a milky solution.

Explanation of incorrect options:

Option A:

1. Hydrogen doesn't evolve in the reaction. Instead, Carbon dioxide is evolved that turns lime-water milky by producing Calcium carbonate.

Option B:

1. The Carbon dioxide gas has no taste and smell so it can't smell like burning sulfur.

Option D:

1. It is the property of Hydrogen that it burns with the pop-up sound but in the reaction, Carbon dioxide is produced, not Hydrogen.

Final Answer: When sodium carbonate is added to a test tube which dilutes hydrochloric acid, carbon dioxide is evolved