Repeated use of which of the following fertilizers would increase the acidity of the soil?

The $pH$ of water is $7$. When a substance $Y$ is dissolved in water,the $pH$ becomes $13$. The substance $Y$ is a salt of......

Predict if the solutions of the following salts are neutral,acidic,or basic: $NaCl, KBr, NaCN, NH_4NO_3, NaNO_2$ and $KF$.

$2.5 \ mL$ of $0.4 \ M$ weak monoacidic base ($K_{b}=1 \times 10^{-12}$ at $25^{\circ} C$) is titrated with $\frac{2}{15} \ M \ HCl$ in water at $25^{\circ} C$. The concentration of $H^{+}$ at equivalence point is ($K_{w}=1 \times 10^{-14}$ at $25^{\circ} C$).

Regular use of which of the following fertilizers increases the acidity of the soil?

The aqueous solution of disodium hydrogen phosphate $(Na_2HPO_4)$ is: