Question

Solution of a monobasic acid has a pH = $5$. If one mL of it diluted to $1$ litre, what will be the pH of the resulting solution?

• A. $3.45$
• B. $6.96$
• C. $8.58$
• D. $10.25$

Answer 1

Answer: (B)

$6.96$

$pH=-log\left[H^{+}\right];\left[H^{+}\right]={10}^{-pH}$

$pH=5;\left[H^{+}\right]={10}^{-5}$

After dilution

$\frac{{10}^{-5}}{1000}={10}^{-8}M$

$Total\left[H^{+}\right]={10}^{-8}+{10}^{-7}=1.1\ast {10}^{-7}$

$pH=-log\left[H^{+}\right]=-log(1.1\ast {10}^{-7})=6.96$