Question

Acid rain is due to dissolved non-metallic oxides $(S{O}_2,N{O}_2,P_2{O}_5,etc.)$ 10 mL of acid rain sample required 5 mL of 0.01 M $Ca(OH{)}_2$ for making it neutral. What is the $pH$ of acid rain?

(Write the answer to the nearest interger value)

Answer 1

The number of moles of hydroxide ions present in calcium hydroxide is $0.01mol/L\times 0.005L=5\times {10}^{-5}mol$.
They will neutralize equal number of moles of hydrogen ions.
Hence, the hydrogen ion concentration is $\frac{5\times {10}^{-5}mol}{0.010L}=5\times {10}^{-3}M$
Hence, the pH of the solution is $pH=-log\left[H^{+}\right]=-log(5\times {10}^{-3})=2.30\approx 2$