Question

Metallic compound A reacts with dilute hydrochloric acid to produce effervescence and a gas B. The gas extinguishes a burning candle and also turns lime water milky. Identify A and B. Write the balanced chemical equations for the reactions involved.

Answer 1

The explanation for the answer:

1. As the gas formed is an effervescent carbon dioxide gas, it happens when Calcium Carbonate$\left({\mathrm{CaCO}}_3\right)$. reacts with hydrochloric acid (HCl).
2. The carbon dioxide gas also acts as an extinguisher for fires.
3. So, the burning candle is extinguished.
4. The metal compound A, therefore, constitutes calcium carbonate.
5. Thus metal compound A is CaCO₃
6. The Gas B evolved is CO₂
7. The balanced equation of the reaction is:$\underset{\mathrm{Calcium}\mathrm{Carbonate}}{{\mathrm{CaCO}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrochloric}\mathrm{acid}}{2\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Calcium}\mathrm{chloride}}{{\mathrm{CaCl}}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{water}\mathrm{or}\mathrm{Oxygen}\mathrm{hydride}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$.

Final Answer:

1. Metal compound A is Calcium Carbonate$\left({\mathrm{CaCO}}_3\right)$.
2. The Gas B evolved is Carbon dioxide $\left({\mathrm{CO}}_2\right)$