Question

When a student adds some dilute hydrochloric acid to baking soda taken in a test-tube, a gas is evolved.
(a) Name the gas evolved.
​(b) How can this gas be tested?

Answer 1

When a student add dilute hydrochloric acid to baking soda(NaHCO₃), the aqueous solution of sodium chloride, carbon dioxide gas, and water are obtained.
$\mathrm{HCl}\left(\mathrm{aq}\right)+{\mathrm{NaHCO}}_3\left(\mathrm{aq}\right)\to \mathrm{NaCl}\left(\mathrm{aq}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

(a) So, the gas evolved is carbon dioxide.

(b) When we pass this gas from lime water, it turns the lime water milky and its presence is confirmed.