How many times would be an aqueous solution of pH = 2 be more acidic than aqueous solution of pH = 4?

Explanation

For solution having pH=4
pH=`-log_(10)[H_(3)O^(+)]`
`therefore-log_(10)[H_(3)O^(+)]=4`
`therefore log_(10)[H_(3)O^(+)]=-4`
`therefore[H_(3)O^(+)]=10^(-4)M`
Similarly,`[H_(3)O^(+)]` for solution having pH=2=`10^(-2)` M.
`([H_(3)O^(+)]"in aqueous solution having pH=2")/([H_(3)O^(+) "in aqueous solution having pH=4"])=(10^(-2)M)/(10^(-4)M)`
Thus,the concentration of `[H_(3)O^(+)]` in concentrated solution of pH=2 will be 100 times more than that of pH=4,i.e. it will be be 100 time more acidic.