The $pH$ of a solution containing $0.10 \ M$ sodium acetate and $0.03 \ M$ acetic acid $(pK_a = 4.57)$ at $298 \ K$ will be ...........

The $pKa$ of a weak acid $HA$ is $4.5$. The $pOH$ of an aqueous buffer solution in which the acid $HA$ is $50\%$ ionized is:

$A$ buffer solution with $pH = 9$ is to be prepared by mixing $NH_4Cl$ and $NH_4OH$. Calculate the number of moles of $NH_4Cl$ that should be added to one litre of $1.0 \ M \ NH_4OH$. $[K_b = 1.8 \times 10^{-5}]$

The $pH$ of a buffer solution prepared by mixing $50 \ mL$ of $0.2 \ M$ $CH_3COOH$ and $250 \ mL$ of $CH_3COONa$ is $4.8$. What is the concentration of $CH_3COONa$ (in $M$)? Given that the $pKa$ of $CH_3COOH$ is $4.8$.

Which of the following may be added to one litre of water to act as a buffer?

$A$ 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: $\log 2 = 0.3010$)