2016 Recalled questions with answer

What is the pH of the solution if the Hydrogen ion concentration is 5 millimoles/L.

a) 2.3
b) 3.7
c) 6.6
d) ?

EXPLN

pH=-log [H+]=log 1/[H+]
[H+]=5millimoles/L=5 x10-3 moles/L
pH=log 1/5 x10-3 moles/L=log 0.2+log 1/10-3=-0.6987+3=3-0.6987=2.3