Ionic Equilibrium question bank (Chemistry)

Consider the dissociation equilibrium of the following weak acid
$\mathrm{HA} \rightleftharpoons \mathrm{H}^{+}(\mathrm{aq})+\mathrm{A}^{-}(\mathrm{aq})$
If the pKa of the acid is 4, then the pH of 10 mMHA solution is $\_\_\_\_$.(Nearest integer)
[Given: The degree of dissociation can be neglected with respect to unity]

An aqueous solution of HCl with pH 1.0 is diluted by adding equal volume of water (ignoring dissociation of water). The pH of HCl solution would
(Given $\log 2=0.30)$