Which of the following salts when dissolved in water will get hydrolysed?

Calculate the hydrolysis constant $(K_h)$ of the salt containing $NO_2^-$. Given the $K_a$ for $HNO_2 = 4.5 \times 10^{-10}$.

$A$ $100 \ mL$, $0.1 \ M$ solution of ammonium acetate is diluted by adding $100 \ mL$ of water. The pH of the resulting solution will be ($pK_{a}$ of acetic acid is nearly equal to $pK_{b}$ of $NH_{4}OH$)

When $CuSO_4$ is hydrated,it becomes:

If $K_a = 1.75 \times 10^{-5}$ and $K_b = 4.6 \times 10^{-10}$,find the hydrolysis constant of anilinium acetate. Given $K_w = 1 \times 10^{-14}$.

The aqueous solution of aluminium chloride $(AlCl_3)$ is acidic due to: