Question

Suppose that you first titrated 25.00mL of 0.500M HCl with 0.500M NaOH and then 25.00mL of 0.500M of your weak acid HA with 0.500M NaOH. How would the titration curves compare at 15.00mL of NaOH beyond the equivalence points?

Answer 1

1) The titration curve for weak acid(HA) vs strong base(NaOH)

Generally a titration curve shows the pH change during a titration,that depends on the strength of acid/base titrated.pH changes slowly for weak acid/base as buffer is formed before equivalence point.

Beyond equivalence point the titrant base NaOH is in excess and pH changes in the same way for weak acid/base or strong acid/base titration

2)The titration curve for strong acid(HCl) vs strong base(NaOH),pH changes in the same way throughout and a steep surge occurs at the equivalence point .

moles of acid titrated=0.5 mol/L*0.025L=0.0125 moles

moles of base added=0.05mol/L*0.015 L=0.0075 moles ..before equivalence