i am sooooooo screwed for chemistry it's not even funnie. ive never been this fucked in this stupid subject

ive done the following question about five times straight and each time i do it, i cant remember how to do it again and MUST REFER BACK TO NOTES aka cheat.

titration of acid HA requires 28.4ml of 0.125 M NaOH until endpoint.

initial pH of HA= 2.628
pH after 14.2 ml NaOH = 4.191

what is original concentration of HA?


HOLY FUCK. DIE TIRATIONS DIE