The $pK_{b}$ of dimethylamine and $pK_{a}$ of acetic acid are $3.27$ and $4.77$ respectively at $T(K)$. The correct option for the $pH$ of dimethylammonium acetate solution is :

Blue litmus turns red in the following mixture of acid and base:

Arrange the following solutions in the decreasing order of $pOH$:
$A$. $0.01 \ M \ HCl$
$B$. $0.01 \ M \ NaOH$
$C$. $0.01 \ M \ CH_3COONa$
$D$. $0.01 \ M \ NaCl$

Equal volumes of three acid solutions with $pH$ values of $3, 4,$ and $5$ are mixed. What will be the concentration of $H^+$ ions in the resulting mixture?

Estimate the approximate $pK_a$ of $0.5 \ M$ $CH_3COOH$. Degree of dissociation (ionisation) is $0.15$ $(\log 1.32 = 0.12)$.

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