Question

A acetic acid $C{{H}_{3}}COOH$ is treated with NaOH solution, which of the following statements is true?
A. Conductance increases up to equivalence point, after which it decreases
B. Conductance decreases up to equivalence point, after which it increases
C. Conductance first increases (but not rapid) up to equivalence point and then increases rapidly after equivalence point.
D. None of the above

Answer 1

Acetic acid is a weak acid and sodium hydroxide is a strong base. The conductometric titration of acetic acid with sodium hydroxide is an example for weak acid and strong base titration. Weak acid conductance is very low when compared to strong base.

Complete step-by-step answer:
- In the question it is asked about the graph which we will get at the time of conductometric titration of acetic acid with sodium hydroxide.
- We know that acetic acid is a weak acid that does not release the hydrogen ion very easily.
- Means at starting the conductance of the acetic acid solution will be less.
- Whenever we are going to add sodium hydroxide (strong base) to the acetic acid solution, the conductance increases slowly due to the neutralization of the acid with base.
- After adding a few ml of sodium hydroxide the titration reaches equivalence point and then we can see a sharp change in the conductance due to the conductance of the hydroxide ion which is liberated from the sodium hydroxide.

Therefore option C is correct.

Note: The point at which there is no presence of acid and base in the titration mixture is called equivalence point. At this point the total amount of acid is completely neutralized with a certain amount of base which is added during the titration.