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 M`
pH = 2 means `[H^(+)]= 10^(-2)M = 0.01 M`
`{:("Applying ",MxxV_(1),=,M_(2)xxV_(2)),(,"(Before dilution)",,"(After dilution)"):}`
`0.1xx1=0.01xxV_(2) "or " V_(2)=10L`
`:.` Volume of water to be added = 10 - 1 = 9 L