How many moles of `NaOH` must be removed from 1 litre of aqueous solution to change its `pH` from 12 to 11

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

How many grams of NaOH must be present in one litre of the solution of give it a pH = 12?

How many litres of water mutt be added to 1 litre of of an aqueous solution of HCl with a pH of 1 to create an aqueous solution with pH of 2

How many litres of water must be added to 1 litre of an aqueous solution of an acid having pH 4.70 to create an aqueous solution having pH 5.70?