Question

The following table shows the type of salt obtained from the neutralisation reaction.

$\begin{array}{cccc}& \text{Acid}& \text{Base}& \text{Type of Salt}\\ \left(i\right)& \text{Nitric acid}& \text{X}& \text{Neutral}\\ \left(ii\right)& \text{Y}& \text{Ammonium hydroxide}& \text{Acidic}\end{array}$

Identify the unknown reactants used inorder to obtain given type of salt.

• A. X- Ammonia
  Y- Carbonic acid
• B. X- Sodium hydroxide
  Y- Acetic acid
• C. X- Ammonium hydroxide
  Y- Acetic acid
• D. X- Potassium hydroxide
  Y- Sulphuric acid

Answer 1

The correct option is D X- Potassium hydroxide

Y- Sulphuric acid
The nature of the salt obtained, from neutralisation reaction, depends upon the strength of the acid and the base.

Case 1: A strong base is required to react with nitric acid (strong acid) in order to obtain a neutral salt, whose pH value will be equal to 7. In the given options, potassium hydroxide $\left(\text{KOH}\right)$ is the strongest base. It will react with nitric acid to form potassium nitrate. The reaction involved is given below:

${\text{HNO}}_3\text{(aq)}+\text{KOH}\text{(aq)}\to {\text{KNO}}_3\text{(aq)}+{\text{H}}_2\text{O}\text{(l)}$

Case 2: A strong acid is required to react with ammonium hydroxide (weak base) in order to obtain an acidic salt whose pH value will be less than 7. In the given options, sulphuric acid $\left({\text{H}}_2{\text{SO}}_4\right)$ is the strongest acid. It will react with ammonium hydroxide to form ammonium sulphate (acidic salt). The reaction involved is given below:

${\text{H}}_2{\text{SO}}_4\text{(aq)}+2{\text{NH}}_4\text{OH}\text{(aq)}\to ({\text{NH}}_4{)}_2{\text{SO}}_4\text{(aq)}+2{\text{H}}_2\text{O}\text{(l)}$