Question

When ammonia, NH3, dissolves in water, hydrogen ions are transferred from the water to ammonia to form ammonium ions and hydroxide ions. This reaction can be seen below:

H2O (l) + NH3 (aq) yields OH- (aq) + NH4+ (aq)

Which of the following helps to explain why ammonia is a base?
a. Arrhenius definition
b. Bronsted- Lowry definition
c. Lewis definition
d. Ionization definition

Answer 1

Bronsted- Lowry definition helps to explain why ammonia is a base.

Step-by-step explanation:

The Brönsted - Lowry theory states that acids are substances capable of yielding protons (hydrogen H⁺ ions) and substance bases capable of accepting them.

Then, the acid-base reaction is one in which a transfer of H⁺ protons occurs from an acid to a base.

A base acid conjugate pair is then produced, where the base conjugate acid is the one formed when the base receives an H⁺; and the conjugate base of the acid, is the base formed when the acid yields an H⁺.

You know this reaction:

H₂O (l) + NH₃ (aq) → OH⁻ (aq) + NH₄⁺ (aq)

In this case you can see that the water acts as an acid, because it gives a proton to the ammonia. Then the ammonia will act as the basis for accepting the proton. The conjugate base of water is the hydroxide ion (OH⁻) and the conjugated acid of ammonia is the ammonium ion (NH₄⁺).

Then, Bronsted- Lowry definition helps to explain why ammonia is a base.

Answer 2

I believe the answer is C. It is the Lewis definition that helps explain why ammonia is a base. According to Lewis' definition, bases donate electrons while the acids accept these electron. In the reaction, ammonia releases electron while the water accepts it.