Q. Determine pH of a 0.01 M aqueous solution of  $Cl{C}_6{H}_{4}N{H}_{3}Cl:$
Given : Kb($Cl{C}_6{H}_{4}N{H}_2$) = 4 x ${10}^{-13}$, log 19 = 1.3, log 2 = 0.3, $\sqrt{16.25}$=4.02 
(A) 2.1 
(B) 2.5 
(C) 3.5 
(D) 3.1