Question

Equal volumes of solutions having pH values $8,10,12$ are mixed with each other, the pH of resultant solution is :

• A. $8.47$
• B. $2.48$
• C. $11.7$
• D. $12.3$

Answer 1

Answer: (A)

$8.47$

$pH=-log\left[H^{+}\right]$

The concentrations of solutions having pH 8, 10 and 12 are $1\times {10}^{-8}M$, $1\times {10}^{-10}M$ and $1\times {10}^{-12}M$ respectively.

The concentration of resulting solution $=\frac{1\times {10}^{-8}M+1\times {10}^{-10}M+1\times {10}^{-12}M}{3}=3.37\times {10}^{-9}M$.

$pH=-log\left[H^{+}\right]=-log(3.37\times {10}^{-9})=8.47$.