Question

Which of the following is an acid salt?

• A. Na₂CO₃
• B. NaHCO₃
• C. NH₄Cl
• D. NaCl

Answer 1

The correct option is B

NaHCO₃

An explanation of the correct option:

The correct option is B:

1. When a base and acid react with each other, salt and water are produced. This reaction is called a Neutralization reaction.
2. The basic equation of neutralization reaction: $\mathrm{acid}+\mathrm{base}\left(\mathrm{alkali}\right)\to \mathrm{salt}+\mathrm{water}$
3. For example, when HCL and NaOH react with each other, salt (NaCl) and water are produced. The reaction between HCl and NaOH is:$\underset{\mathrm{Hydrochloric}\mathrm{acid}}{\mathrm{HCl}\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{hydroxide}}{\mathrm{NaOH}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Sodium}\mathrm{Chloride}}{\mathrm{NaCl}\left(\mathrm{aq}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$
4. As we know, Sodium bicarbonate $\left({\mathrm{NaHCO}}_3\right)$ is formed by mixing carbon, sodium and hydrogen, and oxygen molecules. This mixture, also known as baking soda, is a weak basic salt.
5. Sodium bicarbonate is a basic salt that breaks down in the water to form sodium and bicarbonate. This breakdown forms an alkaline solution, which means it is capable of neutralizing the acid.
6. It gives a basic solution when dissolved in water because the salt ion hydrolysis produces free OH^- ions.
7. The dissociation reaction of Sodium bicarbonate $\left({\mathrm{NaHCO}}_3\right)$ is as follows:$\underset{(\mathrm{Sodium}\mathrm{bicarbonate})}{{\mathrm{NaHCO}}_3\left(\mathrm{s}\right)}\to \underset{(\mathrm{Sodium}\mathrm{ion})}{{\mathrm{Na}}^{+}\left(\mathrm{s}\right)}+\underset{(\mathrm{Bicarbonate}\mathrm{ion})}{{\mathrm{HCO}}_3^{-}\left(\mathrm{s}\right)}$

An explanation of the incorrect options:

Option A:

1. Sodiun carbonate $\left({\mathrm{Na}}_2{\mathrm{CO}}_3\right)$ is a basic salt.
2. It is formed by the combination of sodium hydroxide which is represented by the molecular formula $\mathrm{NaOH}$ and carbonic acid which is represented by ${\mathrm{H}}_2{\mathrm{CO}}_3$.

$\underset{(\mathrm{Sodium}\mathrm{hydroxide})}{2\mathrm{NaOH}\left(\mathrm{s}\right)}+\underset{(\mathrm{Carbonic}\mathrm{acid})}{{\mathrm{H}}_2{\mathrm{CO}}_3\left(\mathrm{l}\right)}\to \underset{(\mathrm{Sodiun}\mathrm{carbonate})}{{\mathrm{Na}}_2{\mathrm{CO}}_3\left(\mathrm{s}\right)}+\underset{\left(\mathrm{Water}\right)}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

Option C:

1. Ammonium chloride $\left({\mathrm{NH}}_4\mathrm{Cl}\right)$ is a by-product of sodium carbonate.
2. Ammonium chloride has diuretic and expectorant effects.
3. In its pure form, it is crystalline acidic salt, white.
4. This compound is highly water-soluble and mildly acidic.
5. The dissociation reaction is as follows:$\underset{(\mathrm{Ammonium}\mathrm{chloride})}{{\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{s}\right)}\to \underset{(\mathrm{Ammonium}\mathrm{ions})}{\mathrm{NH}{4}^{+}\left(\mathrm{aq}\right)}+\underset{(\mathrm{Chloride}\mathrm{ions})}{{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)}$

Option D:

1. Sodium chloride $\left(\mathrm{NaCl}\right)$ is a neutral salt.
2. It is easily soluble in water and partially soluble or insoluble in other liquids.
3. They are white crystals that do not have an odor but possess a taste.
4. In its aqueous state NaCl acts as a good conductor of electricity due to the free movement of the ions.
5. It has a melting point of 801°C and a boiling point of 1,413°C.
6. The dissociation reaction is as follows:$\underset{(\mathrm{Sodium}\mathrm{chloride})}{\mathrm{NaCl}\left(\mathrm{s}\right)}\rightleftharpoons \underset{(\mathrm{Sodium}\mathrm{ion})}{{\mathrm{Na}}^{+}\left(\mathrm{aq}\right)}+\underset{(\mathrm{Chloride}\mathrm{ion})}{{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)}$

Final Answer: Hence, the correct is option (B), NaHCO3 is an acid salt.