When a buffer solution of sodium acetate and acetic acid is diluted with water,

$A$ buffer solution has equal volumes of $0.2 \ M \ NH_4OH$ and $0.02 \ M \ NH_4Cl$. The $pK_b$ of the base is $5$. The $pH$ is

Which of the following does not act as a buffer solution?

$A$ 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 $mL$)

What is the $OH^-$ ion concentration of a solution containing $0.05 \, M$ ammonium hydroxide and $0.001 \, M$ ammonium chloride? Given $K_b(NH_4OH) = 1.8 \times 10^{-5}$.

During the titration of $N/10$ acetic acid with $N/10 \, NaOH$,what is the $pH$ of the solution when $25\%$,$50\%$,and $75\%$ of the titration is complete? $[K_a = 10^{-5}]$