Question

On reacting ${\mathrm{NaHCO}}_3$ and Acetic acid, the gas evolved turns_____

Answer 1

Reaction of ${\mathrm{NaHCO}}_3$ and Acetic acid:

• When Sodium bicarbonate $\left({\mathrm{NaHCO}}_3\right)$reacts with acetic acid, a neutralization reaction takes place and an aqueous salt of Sodium bicarbonate is formed along with the evolution of Carbon dioxide gas.

$\underset{\mathrm{Acetic}\mathrm{acid}}{{\mathrm{CH}}_3\mathrm{COOH}\left(\mathrm{l}\right)}+\underset{\mathrm{Sodium}\mathrm{bicarbonate}}{{\mathrm{NaHCO}}_3\left(\mathrm{s}\right)}\to \underset{\mathrm{Sodium}\mathrm{acetate}}{{\mathrm{CH}}_3\mathrm{COONa}\left(\mathrm{aq}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}+\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}$

• The gas evolved in the reaction is carbon dioxide, which is a colorless and odourless gas.
• When this Carbon dioxide reacts with limewater to form a white precipitate (which appears milky) of Calcium carbonate$\left({\mathrm{CaCO}}_3\right)$.

$\underset{\mathrm{Calcium}\mathrm{hydroxide}}{\mathrm{Ca}\left(\mathrm{OH}{)}_2\right(\mathrm{aq})}+\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}⟶\underset{\mathrm{Calcium}\mathrm{carbonate}}{{\mathrm{CaCO}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

Therefore, On reacting ${\mathrm{NaHCO}}_3$ and Acetic acid, the gas evolved turns lime water milky.