Question

Identify the acid and base which form sodium hydrogen carbonate . Write chemical equation in support of your answer. State whether its compound is acidic, basic or neutral. Also write its pH value.

Answer 1

Part 1: Identify the acid and base which form Sodium Hydrogen Carbonate (${\mathbf{NaHCO}}_{\mathbf{3}}$)

• Salt hydrolysis is a process in which salt reacts with water to give back the acid and base from which that salt is formed.
• The salt hydrolysis of Sodium hydrogen carbonate produces the base sodium hydroxide and carbonic acid.
• The balanced chemical reaction of salt hydrolysis can be written as:

$\underset{\mathrm{Sodium}\mathrm{Hydrogen}\mathrm{Carbonate}}{{\mathrm{NaHCO}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sodium}\mathrm{Hydroxide}}{\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Carbonic}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{CO}}_3\left(\mathrm{aq}\right)}$

• Hence, the acid and base are Carbonic acid and Sodium hydroxide respectively.

Part 2: Identify the nature of Sodium Hydrogen Carbonate

• Sodium Hydrogen Carbonate (${\mathrm{NaHCO}}_3$) is formed by the neutralization of a weak Carbonic acid by a strong base Sodium hydroxide.
• Hence, Sodium hydrogen carbonate is an basic salt.
• Therefore, the $\mathrm{pH}$ of Sodium hydrogen carbonate is $8.3$.

Therefore, The acid and base used are Sodium Hydroxide ($\mathrm{NaOH}$) and Hydrogen carbonate (${\mathrm{H}}_2{\mathrm{CO}}_3$) and the $\mathrm{pH}$ is $8.3$.