316411
Regular use of which of the following fertiliser increases the acidity of soil:
1 Urea
2 Superphosphate
3 Ammonium sulphate
4 Potassium nitrate
Explanation:
\(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}\) is a salt of strong acid and weak base, on hydrolysis it will produce \(\mathrm{H}^{+}\) ion. This will increase the acidity of soil. \(\begin{aligned}& \left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4} \longrightarrow 2 \mathrm{NH}_{4}^{+}+\mathrm{SO}_{4}^{2-} \\& \mathrm{NH}_{4}^{+}+\mathrm{H}_{2} \mathrm{O} \square \quad \mathrm{NH}_{4} \mathrm{OH}+\mathrm{H}^{+}\end{aligned}\)