Polyprotic-Acids and Bases

Question 1

What is a polyprotic acid?

Answer 1

Polyprotic acids are acids that contain more than one ionizable hydrogen atom. Sulfuric acid is an example of a diprotic polyprotic acid.

Question 2

Describe the stepwise dissociation of a diprotic acid?

Answer 2

The dissociation of diprotic acids occurs in two steps;
- the first step is when the first proton is transferred to a different atom.
-The second step is when the second proton is donated to another atom.

Question 3

Explain how the pH changes with each dissociation step in polyprotic acids

Answer 3

The weak polyprotic acid dissociates, the proton (H+) combines with H2O to form H30+. The concentrations of both A- and HA are equal, therefore [A-] [HA] = 1, pH = pka + log(1)

Question 4

What is a polyprotic base and how does it differ from a polyprotic acid?

Answer 4

Polyprotic acid and base they can donate or accept more than one proton

Question 5

Provide an example of a polyprotic base and its reaction in water

Answer 5

Ammonium hydroxide is dissolved in water; NH4OH + H2O –> NH4 + OH-