Question

In the Ksp experiment, from the titration curve for OH^-, the volume of HCl used to reach the equivalence point is determined

a) from the vertical region where the pH made the greatest decrease as HCl was added.

b) from the point of maximum pH.

c) from the point of minimum pH.

Answer 1

a)

the vertical region where pH is greates is about pH = 7

b)

the HCl when pH is max, is when all base is added

c)

the min pH is before any addition of OH- base

ADDITIONAL NOTES:

The ksp experiment you are probably using a precipitant such as

Fe(OH)3 ; Ba(OH)2; Ca(OH)2 ; Al(OH)3, etc...

Then you used HCl to titrate those OH- ions

therefore

since this is strong acid - strong base reaction; expect a very drastic chang ein pH when neutralization occurs

i.e.

the answer is A)

a) from the vertical region where the pH made the greatest decrease as HCl was added.