What is the $pH$ of a buffer solution formed by mixing $0.01 \ M$ acetic acid and $0.05 \ M$ sodium acetate $(pK_a = 4.7447)$?

$A$ 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 solutions cannot act as a buffer?

The $pH$ of a sodium acetate buffer solution is given by the Henderson-Hasselbalch equation: $pH = pK_a + \log \frac{[Salt]}{[Acid]}$. For acetic acid,if $[Salt] = [Acid] = 0.1 \ M$,then the $pH$ of the solution is: $[K_a = 1.8 \times 10^{-5}]$

$A$ $0.15 \text{ mol}$ of pyridinium chloride is added to $500 \text{ cm}^3$ of $0.2 \text{ M}$ pyridine solution. Assuming no change in volume upon mixing, what is the $pH$ of the resulting solution? (Given: $pK_b$ of pyridine $= 8.75$)

To prepare a buffer solution of $pH = 6$ by mixing sodium acetate and acetic acid,what should be the ratio of the concentration of salt to acid? $(K_a = 10^{-5})$