Comparison of Bronsted-Lowry and Arrhenius theories

Question 1

Name the 5 main comparisons of the bronsted-lowry and arrhenius theories

Answer 1

1. The Arrhenius theory is limited to reactions in water whereas the Bronsted-Lowry theory is not limited to reactions in water but also applies to gaseous reactions and solvents other than water.
2. The Arrhenius theory is limited to bases that produce hydroxide ions in water but not all bases produce hydroxide ions, e.g. there are no oxygen atoms in NH3 so it is impossible for it to produce OH- ions.
3. Substances that would not be classified as acids or bases in the Arrhenius theory are classified as acids or bases in the Bronsted-Lowry theory. It broadens the range of species that can be defined as acids and bases.
4. The Arrhenius theory does not take the existence of hydronium ions into account but the Bronsted-Lowry theory does.
5. The Arrhenius theory cannot explain how a substance can act as both an acid and a base but the Bronsted-Lowry theory explains it in terms of proton transfer.

Question 2

The Arrhenius theory is limited to reactions in water whereas the Bronsted-Lowry theory is not limited to reactions in water but also applies to gaseous reactions and solvents other than water.
Give an example of this applied.

Answer 2

In the reaction between HCl and NH3, in liquid ammonia or in the gaseous state, the hydrogen chloride molecule acts as an acid by donating a proton to the ammonia molecule. No water molecules are present.

Question 3

Substances that would not be classified as acids or bases in the Arrhenius theory are classified as acids or bases in the Bronsted-Lowry theory. It broadens the range of species that can be defined as acids and bases.
Give an example of this applied.

Answer 3

The action of NH3 as a base can be explained by the Bronsted-Lowry theory but not by the Arrhenius theory