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

Which one of the following salts gives an acidic solution in water?

When a salt of a weak acid and a weak base is dissolved in water at $25\,^{\circ}C$,the $pH$ of the resulting solution will always :-

If the $pK_a$ value of $CH_3COOH$ is $4.74$,then the $pH$ value of $0.1 \ M \ CH_3COONa$ is ......

When $C_6H_5NH_3^+ Cl^-$ salt is dissolved in water,it undergoes hydrolysis. Find the equilibrium constant of the hydrolysis reaction if the ionization constant of the weak base is $10^{-4}$.

The concentration of $[H^{+}]$ in a $0.1 \, M \, CH_3COONa$ solution [$K_a = 10^{-5}$] is equal to ......