Which among the following salts turns red litmus blue in its aqueous solution?

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

The correct relationship between the hydrolysis constant $(K_h)$ and the dissociation constant $(K_b)$ for $MgCl_2$ is:

The $pH$ of the solution obtained on neutralization of $40 \ mL \ 0.1 \ M \ NaOH$ with $40 \ mL \ 0.1 \ M \ CH_3COOH$ is

$2.5 \ mL$ 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 $25^{\circ} C$).

Calculate the hydrolysis constant $(K_h)$ for a salt containing $NO_2^-$. Given that the dissociation constant $(K_a)$ for $HNO_2$ is $4.5 \times 10^{-4}$ and the ionic product of water $(K_w)$ is $1.0 \times 10^{-14}$.