$A$ solution of formic acid is half-neutralized by the addition of a $KOH$ solution. If $K_a (HCOOH) = 2 \times 10^{-4}$,what is the $pH$ of the solution? (Given: $\log 2 = 0.3010$)

Find the $pH$ when $0.2 \, mol$ of $HCl$ is added to $1 \, L$ of a solution containing $1 \, M$ $CH_3COOH$ and $1 \, M$ $CH_3COO^-$. Assume the total volume remains $1 \, L$. Given $K_a$ for $CH_3COOH = 1.8 \times 10^{-5}$.

Henderson's equation is $pH = pK_a + \log\frac{[\text{salt}]}{[\text{acid}]}$. If the acid is half-neutralized,the value of $pH$ will be: $[pK_a = 4.30]$

$A$ buffer solution is prepared by mixing $0.01 \ M$ $HCN$ and $0.02 \ M$ $NaCN$. If $K_{a}$ for $HCN$ is $6.6 \times 10^{-10}$,what is the concentration of $H^{+}$ ions in the solution?

Which of the following solutions will act as a buffer solution?

The $pH$ of blood in the human body is maintained by $CO_2$ and $H_2CO_3$. What is this process called?