Question

Metal compound A reacts with dilute Hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is Calcium chloride.

Answer 1

Understanding the chemical reaction:

• Calcium carbonate reacts with dil hydrochloric acid to form calcium chloride and carbon dioxide is released as a by-product.
• The gas evolved as carbon dioxide and is responsible for extinguishing the burning candle.
• The balanced chemical equation to demonstrate the above-mentioned explanation can be given as:

$\underset{\left(\mathrm{Calcium}\mathrm{Carbonate}\right)}{{\mathrm{CaCO}}_3\left(\mathrm{s}\right)}+\underset{\left(\mathrm{Hydrochloric}\mathrm{acid}\right)}{2\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{\left(\mathrm{Calcium}\mathrm{chloride}\right)}{{\mathrm{CaCl}}_2\left(\mathrm{s}\right)}+\underset{\left(\mathrm{Carbon}\mathrm{dioxide}\right)}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\left(\mathrm{Water}\right)}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

• Therefore, here the metal compound A is calcium carbonate and the effervescent is carbon dioxide.