$A$ buffer solution of $pH = 9.80$ is to be prepared from $1 \ M \ NH_4Cl$ and $1 \ M \ NH_3$ solution. $pK_{b}$ of $NH_3$ is $4.74$. In $1 \ L$ of the buffer solution,the volume of $NH_4Cl$ solution required is $(\log 0.28 = -0.54) :-$ (in $mL$)

$0.1 \ M, 60 \ mL$ $NH_4Cl$ $(K_h = 10^{-9})$ is titrated against $0.2 \ M$ $NaOH$. What is the $pH$ at the $\frac{1}{3}$ equivalence point?

$20$ mL of a solution of acetic acid required $28.4$ mL of $0.1$ $M$ NaOH for its neutralization. $A$ solution $(X)$ was prepared by mixing $20$ mL of the above acetic acid and $14.2$ mL of $0.1$ $M$ NaOH solution. What is the pH of the solution $(X)$? ($pK_a$ value of acetic acid is $4.75$).

$0.1 \ mol$ of $CH_3NH_2$ $(K_b = 5 \times 10^{-4})$ is mixed with $0.08 \ mol$ of $HCl$ and diluted to $1 \ L$. The $[H^{+}]$ in the solution is:

How many moles of sodium acetate should be added to $1 \ L$ of a $0.1 \ M$ solution of $CH_3COOH$ to give a solution of $pH = 5.5$? (Given: $pK_a$ of $CH_3COOH = 4.5$)

Which of the following mixtures will form a buffer solution?