the hydrogen ion concentration can be calculated using pH
pH = -log [H⁺]
when pH is known antilog of pH needs to be calculated
[H⁺] = antilog (-pH)
when pH = 11
[H⁺] = antilog(-11)
[H⁺] = 1 x 10⁻¹¹ mol/L
when pH = 6
[H⁺] = antilog (-6)
[H⁺] = 1 x 10⁻⁶ mol/L
then to find how much fewer H⁺ ions at pH = 11 than when pH = 6, we have to find the ratio.
ratio = (1 x 10⁻¹¹ mol/L) / (1 x 10⁻⁶ mol/L)
there's 10⁻⁵ lesser H⁺ ions when pH - 11 than when pH - 6
