Question

Suppose that you are performing a titration on a monoprotic acid. Titration of this monoprotic acid required a volume of 0.1L of the base being used. If the same volume of a diprotic acid would instead have been used (same volume of a diprotic acid versus the originally used monoprotic acid), and if we assume furthermore that the concentration of the diprotic acid and the monoprotic acids are equal, how does the volume of base required to reach the endpoint for the diprotic acid compare to the volume of base required to reach the endpoint for the monoprotic acid?
A) More base is likely required to reach the endpoint for the diprotic acid than for the monoprotic acid under these conditionsB) Less base is likely required to reach the endpoint for the diprotic acid than for the monoprotic acid. C) Exactly the same amount of base is required for both monoprotic and diprotic acids under the situations described here.D) A completely different indicator will need to be used here.

Answer 1

Answer: A) More base is likely required to reach the endpoint for the diprotic acid than for the monoprotic acid under these conditions

Explanation:

The monoprotic acid (HA) has a valency of 1 and diprotic acid  $(H_2A)$ has a valency of 2.

As the concentration and volume of the diprotic acid and the monoprotic acids are equal.

The neutralization reaction for monoprotic acid is:

$HA+BOH\rightarrow BA+H_2O$

The neutralization reaction for diprotic acid is:

$H_2A+2BOH\rightarrow B_2A+2H_2O$

Thus more number of moles of base are required for neutralization of diprotic acid and thus the volume required will be more as concentration and volume of the diprotic acid and the monoprotic acids are equal.