How many litres of water must be added to `1 L` of an aqueous solution of `HCl` with a `pH` of `1` to create an aqueous solution with `pH` of `2`?

Options

A. 0.1L
B. 0.9L
C. 2.0L
D. 0.9L

Answer

D

Explanation

pH=1
`therefore [H^(+)]=10^(-1)=0.1M`
`therefore [H^(+)]=10^(-2)=0.01M`
For dilution of HCl, `M_(1)V_(1)= M_(2)V_(2)`
`0.1xx1=0.01xxV_(2)`
`V_(2)=10L`
Volume of water to be added 10-1=9L