Titration Question

Question

I have absolutely no idea how to do this and do not even know what to search even if I did need help.  The question is; If the base solution is 0.250 M and there is one equivalent of OH- ions for each mole of base, how many moles of OH- ions are consumed at the end point of the titration?

Answer 1

Let's assume the base is NaOH.  With this base, you have 0.25 mols of Na+ and 0.25 mols of OH- (the one equivalent OH- ion asked for in the question).  The key word here is "end point."  At the end point of a titration, a color change of the chemical indicator occurs (say from clear to slightly pink, indicating a pH change).  At this moment your titration experiment should end, as you have surpassed your equivalence point (the point where the concentration of your OH- is equivalent with the concentration of H+).  Knowing this, one can say that 0.25 mols of the hydroxide ions were consumed at the end point of this titration.