The plot of $pH$-metric titration of weak base $NH_4OH$ vs strong acid $HCl$ looks like:

Arrange the following $0.1 \ M$ salt solutions in increasing order of their $pH$:

Equal volumes of aqueous solution of $0.1 \ M \ HCl$ and $0.2 \ M \ H_2SO_4$ are mixed. The concentration of $H^{+}$ ions in the resulting solution is (in $M$)

Which of the following statement$(s)$ is/are correct.
$A$. The $pH$ of $1 \times 10^{-8} \ M$ aqueous solution of $HCl$ is $8$
$B$. The conjugate base of $H_2PO_4^{\ominus}$ is $HPO_4^{2-}$
$C$. $K_w$ increases with increase in temperature
$D$. When a solution of a weak monoprotic acid is titrated against a strong base,then at the half-neutralization point,$pH = pK_a$.

At $25^{\circ}C$,$20.0 \ mL$ of $0.2 \ M$ weak monoprotic acid $HX$ is titrated against $0.2 \ M$ $NaOH$. The $pH$ of the solution $(a)$ at the start of the titration (when $NaOH$ has not been added) and $(b)$ when $10 \ mL$ of $NaOH$ is added respectively,are:
Given: $K_a = 5 \times 10^{-4}, pK_a = 3.3, \alpha << 1$

What is the $pH$ of a solution containing $10 \, mL$ of $0.1 \, M \, NaOH$ and $10 \, mL$ of $0.05 \, M \, H_2SO_4$?