Question

a)What happens when dilute hydrochloric acid is added to sodium carbonate? Write a balanced chemical equation of the reaction evolved.
b)Which gas is liberated when dilute hydrochloric acid reacts with sodium carbonate? How will you test for the presence of this gas?

Answer 1

Hint : Sodium carbonate is a base, and hydrochloric acid is a strong acid when sodium carbonate is treated with acid like hydrochloric acid form an ionic salt, the salt will be sodium chloride along with the formation of water and liberation of carbon dioxide gas.

Complete Step By Step Answer:
Given that dilute hydrochloric acid is added to sodium carbonate. Dilute hydrochloric acid is an acid with the molecular formula of $HCl$ and sodium carbonate is a base with the molecular formula of $N{a_2}C{O_3}$ .
The balanced chemical equation has the same number of atoms on both sides of the reactants and products. The balanced chemical equation when dilute hydrochloric acid is added to sodium carbonate will be as follows:
$N{a_2}C{O_{3\left( s \right)}} + 2HC{l_{\left( l \right)}} \to 2NaC{l_{\left( {aq} \right)}} + C{O_{2\left( g \right)}} + {H_2}{O_{\left( {aq} \right)}}$
Thus, the gas evolved in the above reaction is carbon dioxide. When this carbon dioxide is formed in the form of brisk effervescence. When these brisk effervescences are passed through milky lime water, the solution becomes clear. The formation of a clear solution indicates the presence of carbon dioxide gas.

Note :
Lime water can be formed when calcium hydroxide treated with water forms an alkali solution. When the carbon dioxide is passed through the alkaline solution i.e.., lime water calcium carbonate can be formed which will be known by the turning of clear solution from milky solution.