Question

If i titrated 25.0mL of 0.500M HCl with 0.500M NaOH and then 25.0mL of 0.500M of an unknown weak acid HA with 0.500M NaOH. How would the two titration curves compare at 10 or 15mL of NaOH Beyond equivelance pts? I think that they will be the ssame or similar but i don't know how to explain why ...

Answer 1

I can't draw on this forum how these things look; however, remember that with the HA, adding NaOH produces a buffered solution. Because it's a weak acid the initial pH (before any NaOH is added) is higher and the addition of NaOH forms NaA. The mixture of unreacted HA and the NaA formed produces a buffer. The vertical part of the titration curve is shortened and the pH at the equivalence point is higher (7.0 with HCl and about 8.5 with HA). The pH after the equivalence point is essentially unchanged between the two. You can go to google and type in titration curves or something like that and get pictures of how they look. If you can't find them, repost and I'll look.

Answer 2

0.500\40=0.0125
0.0125\0.025=0.5