When $NaCl$ is dissolved in water,the sodium ion is

The degree of dissociation of $0.01 \ M$ solution of $NH_4OH$ is $4.2 \times 10^{-2}$. What is the percent dissociation of $NH_4OH$ (in $\%$)?

The concentration of $[H^{+}]$ and concentration of $[OH^{-}]$ of a $0.1 \ M$ aqueous solution of $2\%$ ionised weak acid is [Ionic product of water $= 1 \times 10^{-14}$]

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

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.

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