Question

An acid solution of $pH$ $6$ is diluted hundred times. The $pH$ of resulting solution approximately becomes:

• A. $6.95$
• B. $6$
• C. $4$
• D. $9$

Answer 1

Answer: (A)

$6.95$

We assume that one part of acid is diluted with $99$ parts of distilled water being at $pH=7$ contains ${10}^{-7}mol/L$ of hydronium ions.

$\left[H_3{O}^{+}\right]=0.99\times 1\times {10}^{-7}+\left(0.01\right)\times \left(1.0\right)\times \left({10}^{-6}\right)=1.09\times {10}^{-7}$

$pH=-log\left[H^{+}\right]⟹pH=6.95$