Question

Ammonium sulphate has:
A. Acidic pH
B. Basic pH
C. Neutral pH
D. Both a and c

Answer 1

Hint: Ammonium Sulphate ${(NH}_4{)}_2{SO}_3$ is produced by the reaction between sulphuric acid and ammonium hydroxide. Sulphuric acid is a strong acid while ammonium hydroxide is a weak base.

Complete step-by-step answer:
As it is a salt of strong acid and weak base, its solution is acidic. The following reactions will takes place;
${(NH}_4{)}_2{SO}_3\to {2NH}_4^{+}+{SO}_4^{2-}$
When ammonium sulphate is dissolved in water, ammonium ion,sulphate ion, hydrogen ion and hydroxide ions are formed. When ammonium ion and hydroxide ions are combined to form ammonium hydroxide which is a weak base which is less dissociated.
${NH}_3+H_{2}O\to {NH}_4^{+}+{OH}^{-}$
As we know that ammonia is a weak base that forms conjugate acid and when dissolved in water whereas ammonium sulphate is a salt that dissociates into ions when dissolved in water.
${2H}^{+}+{SO}_4^{2-}\to H_2{SO}_4$
Generation of $H^{+}$ ions makes the solution acidic and it turns blue litmus red.
Hence, it is an acidic salt as the acidic character of strong acid dominates over the weak basic character in the salt and its pH < 7.
So, Correct option is A.

Additional Information:
It is an inorganic salt and it has many commercial uses. Mostly, it is used as a soil fertilizer for alkaline soils.
It is also used as an agricultural spray for insecticides, herbicides and fungicides. It had some laboratory uses like for protein purification by precipitation.

Note: The possibility for the mistake is that you can choose the option (d) as you might get confused that it can also show neutral pH (pH = 7) as it is formed when an acid and base reacts it will become neutral. But a strong acid and a weak base are reacting, so it will be acidic in nature.