TOLC MED 2020 Q42 pH calc

I think this paper is an A Form paper, can someone point what i’ve done wrong?

Wouldn’'t you have to divide by half at some point to work out molar concentration?

I might be wrong but not there I know of… isn’t the formula like pH = -log[H+]?

Yeah, but what I did (not 100% sure on it) was doing it the opposite way:
Knowing [H+] = 10^-pH , I did the same with OH- and pOH
[OH-] = 10^-2
which is what you’ve done, but because theres 2 OH moles for every mole of Sr(OH)2, i divided by 2 which gets A

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