Which buffer solution out of the following will have $pH > 7$?

The $pK_b$ of $CN^{\Theta}$ is $4.7$. The $pH$ of a solution prepared by mixing $2.5 \ mol$ of $KCN$ and $2.5 \ mol$ of $HCN$ in water and making the total volume up to $500 \ mL$ is:

The $pH$ of blood is

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:

$A$ certain acidic solution contains equal concentrations of $X^-$ and $HX$. If $K_b$ for $X^-$ is $10^{-10}$,then the $pH$ of the buffer is equal to:

In an acidic buffer,$0.25 \ M$ $CH_3COOH$ is added to $0.125 \ M$ $NaCH_3COO$ solution. Calculate the $pH$ of the buffer. Given $K_a$ of $CH_3COOH = 1.8 \times 10^{-5}$. [Formula: $pH = pK_a + \log \frac{[Salt]}{[Acid]}$]