We're studying acids and bases; the question states that 50mL of 0.1M HNO3 solution is mixed with 25mL of 0.1M NaOH. What is the pH? I thought that I would use the Henderson-Hasselbach equation; but my answer does not match the one give in the solution. Any help?
Henderson equations deal with a weak acid or base salt. Here that is Not the case.
the lye neutralized half the acid...so you have started with a volume of .050liter. Moles of acid was .1*.050=.005 moles. You are left .0025 moles acid in a volume of .075 liters (you added 25ml)
pH=-log(.0025/.075)=1.48 check that.