To classify the role of water in the given chemical reaction:
[tex]\[ NH_3(g) + H_2O (\ell) \rightarrow NH_4^+ (aq) + OH^- (aq) \][/tex]
we need to examine how water participates in this reaction according to the Brønsted-Lowry theory. The Brønsted-Lowry definition states:
- An acid is a substance that donates a proton (H⁺).
- A base is a substance that accepts a proton (H⁺).
Let's look at what happens in the reaction:
1. Ammonia [tex]\( NH_3 \)[/tex] gains a proton (H⁺) to form ammonium [tex]\( NH_4^+ \)[/tex].
2. Water [tex]\( H_2O \)[/tex] loses a proton (H⁺) to form hydroxide ion [tex]\( OH^- \)[/tex].
In this reaction:
- Water [tex]\( H_2O \)[/tex] donates a proton to ammonia, resulting in the formation of the hydroxide ion.
- Ammonia [tex]\( NH_3 \)[/tex] accepts the proton from water, resulting in the formation of the ammonium ion.
According to the Brønsted-Lowry definition:
- Because water [tex]\( H_2O \)[/tex] donates a proton, it behaves as a Brønsted-Lowry acid in this reaction.
Therefore, the correct classification of water in this reaction is:
A. As a Brønsted-Lowry acid, because it donates a proton.
