The $pH$ of $0.1 \ M$ solution of the following salts increases in the order:

$A$ certain amount of $H_2CO_3$ and $HCl$ are dissolved to form $1 \ L$ solution. At equilibrium,it is found that the concentrations of $H_2CO_3$ and $CO_3^{2-}$ are $0.1 \ M$ and $0.01 \ M$ respectively. Calculate the $pH$ of the solution. Given that for $H_2CO_3$,$K_{a_1} = 10^{-5}$ and $K_{a_2} = 10^{-8}$.

The $pH$ value of a decinormal solution of $NH_4OH$ which is $20\%$ ionised,is

If $10\%$ of a $5 \times 10^{-3} \, M \, H_2CO_3$ solution dissociates,then the concentration of $H^{+}$ ions is equal to $......$.

Statement $A$: $pH$ of a buffer increases with increasing temperature. Statement $B$: The value of $K_W$ of water decreases with decreasing temperature.

Which one of the following statements is correct?