Find the value of $\frac{[NaCN]}{[HCN]}$ given the $pH$ of the buffer solution of $NaCN$ and $HCN$ is $9.3$ and $K_a$ of $HCN$ is $5 \times 10^{-10}$.

For a $10 \, mL$ solution containing $0.1 \, M \, NH_4Cl$ and $0.01 \, M \, NH_4OH$,which of the following additions will not change the $pH$ of the solution?

$2 \ g$ acetic acid and $3 \ g$ sodium acetate are present in $100 \ mL$ aqueous solution. What will be the $pH$ of the solution if the ionisation constant of acetic acid is $1.8 \times 10^{-5}$?

Which of the following solutions can act as a buffer?

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

$A$ weak acid,$HA$,is found to be $10\%$ ionized in $0.01\ M$ aqueous solution. Calculate the $pH$ of a solution which is $0.1\ M$ in $HA$ and $0.05\ M$ in $NaA$.