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

Answer

A

Explanation

`pH=1 `means `|H^(+)|=10^(-1)M =0.1`
`Ph =2 ` means `|H^(+)|=10^(-2)M=0.2 M`
Now `M_(1) xx V_(1)=M_(2)xx V_(2)`
Before dilution After dilution
`0.1 xx 1 =0.01 xx V_(2) ` or `V_(2)=10L`
`:. `Volume of water to be added `10-1=9L`