20ml sample of .200M HBr is titrated w/ .200M NaOH. what is the ph after adding 15ml (base)?

1 answer

HBr + NaOH ==> NaBr + HOH

Calculate mols HBr.
mols HBr = M x L = ??
Calculate mols NaOH used = M x L.

Subtract mols of one from mol of the other. The one in excess will give you the H^+ if it is HBr or OH^- if it is NaOH.
Then pH = -log(H^+) OR
pOH = -log(OH^-)