$A$ solution contains $8 \, g$ of $NaOH$ and $4.9 \, g$ of $H_2SO_4$ in $1 \, L$ of solution. What is its $pH$?

$A$ weak acid is titrated with a weak base. Consider the following statements regarding the $pH$ of the solution at the equivalence point.
$(i)$ $pH$ depends on the concentration of acid and base
$(ii)$ $pH$ is independent of the concentration of acid and base
$(iii)$ $pH$ depends on the $pK_{a}$ of acid and $pK_{b}$ of base
$(iv)$ $pH$ is independent of the $pK_{a}$ of acid and $pK_{b}$ of base
The correct statements are

For a $0.01 \ M \ HCN$ solution,the van't Hoff factor is $1.002$. What will be the acid dissociation constant $(K_a)$ for $HCN$?

For a weak acid $HCN$ at $25 \, ^\circ C$,which of the following statements is correct?

When a standard solution of $NaOH$ is left in the air for a few hours,

Statement $A$: Addition of $NH_4OH$ in the presence of excess $NH_4Cl$ to an aqueous solution of $BaCl_2$ results in the precipitation of $Ba(OH)_2$.
Reason $B$: $Ba(OH)_2$ is insoluble in water.