Which of the following is not a buffer solution?

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

Explain the preparation of an acidic buffer solution with an example.

Calculate the $pH$ of a $0.10 \,M$ ammonia solution. Calculate the $pH$ after $50.0 \,mL$ of this solution is treated with $25.0 \,mL$ of $0.10 \,M$ $HCl$. The dissociation constant of ammonia,$K_{b} = 1.77 \times 10^{-5}$.

$50 \ mL$ of $2 \ N$ acetic acid mixed with $10 \ mL$ of $1 \ N$ sodium acetate solution will have an approximate $pH$ of:

Buffer solution is prepared by mixing