The aqueous solution of which of the following will have the highest $pH$?

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

$NH_4CN$ is a salt of a weak acid $HCN$ $(K_a = 6.2 \times 10^{-10})$ and a weak base $NH_4OH$ $(K_b = 1.8 \times 10^{-5})$. $A$ $1 \ M$ solution of $NH_4CN$ will be:

If the value of $K_b$ is $10^{-5}$,find the $K_h$ value for a salt of (strong acid - weak base) at $363 \ K \ (90 \ ^\circ C)$. [At $90 \ ^\circ C, K_w = 10^{-12}$]

$A$ weak acid $HX$ $(K_a = 10^{-5})$ on reaction with $NaOH$ gives $NaX$. For $0.1 \ M$ aqueous solution of $NaX$,the $\%$ hydrolysis is $....... \ \%$.

$NH_4Cl$ is acidic,because