Which of the following has the highest degree of hydrolysis?

Calculate the $pH$ of a $1.0 \, M$ ammonium formate solution,given that $K_a = 1 \times 10^{-4}$ and $K_b = 1 \times 10^{-5}$.

Which of the following aqueous solutions will be most basic?

The aqueous solution of copper sulfate is acidic because...

$A$ weak acid $HX$ has the dissociation constant $1 \times 10^{-5} \ M$. It forms a salt $NaX$ on reaction with alkali. The degree of hydrolysis of $0.1 \ M$ solution of $NaX$ is......$\%$

Explain the following with reasons:
$(i)$ $NaCl$ solution is neutral. The solution of strong acid and strong base salts is neutral.
$(ii)$ $NaCH_3COO$ solution is basic. The solution of strong base and weak acid salt is basic.
$(iii)$ $NH_4Cl$ solution is acidic. The solution of weak base and strong acid salt is acidic.
$(iv)$ The solution of $NH_4CH_3COO$ is (almost) neutral. The solution of weak acid - weak base salts is almost neutral.