For a weak acid $(HA)$,$pK_a = 4.5$. The $pOH$ of a buffer solution of $HA$ in which $50\%$ of the acid is ionized is:

Which of the following does not act as a buffer solution?

Study the following table:

Buffer Solution	Volume (in $mL$) of $0.1 \ M$ Weak acid	Volume (in $mL$) of $0.1 \ M$ sodium salt of weak acid
$I$	$4.0$	$4.0$
$II$	$4.0$	$40.0$
$III$	$40.0$	$4.0$
$IV$	$0.1$	$10.0$

Which of the two sets of buffer solutions have the least $pH$?

Which of the following is a buffer solution?

$pH$ of a mixture which is $0.1 \ M$ in $CH_3COOH$ and $0.05 \ M$ in $(CH_3COO)_2Ba$ is [$pK_a$ of $CH_3COOH$ = $4.74$]

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