My question is, that i could just use logic without having to do a lot of math to get this answer correct but it did not come out correct so i want to know what is flawed ?

HBr is a strong acid and we have 6 * 10 ^-4

KOH is a strong base and we have 12 * 10 ^-4

----- Even though this has nothing to do with titrations this was my thinking: From my titration notes I know that at the equivalence point of a Strong acid and a Strong base (which is the point we have equal amount of acid and equal amounts of base) the PH will be 7.

So then I thought that here we have acid and base at a ratio of 6 :12 which breaks down to a 1:2 ratio. So we have two times as much base. So I know the answer must be basic, but now the question is by approximately how much? Then I though that since the ratio is basically a 1:2 ration then we should have the ph increase into basic conditions by only one factor of 10 which would put the ph at around 8 for the final answer.

But damn I was wrong the answer is 12. My logic came from my notes in my Buffer and Titration chapters, even though I know this is not a buffer but a strong base and a strong acid = 7 in a titration at a 1:1 ratio should still be true but then why would it not be an increase by 1 factor of 10. why does this not work here