The Student Room Group

acid base equlibiria

q)The student made the following statement:
‘The pH of pure water is always 7.0’
Is the student correct? Use the following information to justify your answer.
H2O(l) H+(aq) + OH–(aq)
Kw = 1.0 x 10–14 mol2 dm–6 at 298 K
deltaH is positive for the forward reaction in the equilibrium.

the mark scheme says equilbrium moves to right therefore H+ ions increase and ph decreases. However doesn't that also mean OH- conc increases which would make it neutral?
pH is a measure of how many hydrogen ions are present in a solution. the greater the [H+], the lower the pH
yes, neutral means that [H+] = [OH-]
but
neutral does not necessarily mean pH 7

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