In the reversible reaction in water solution
NH3 + H2O <---> NH4+ + OH− ,
what acts as a Bronsted-Lowry acid and what acts as a Bronsted-Lowry base?
1. H2O; NH4+
2. H2O; OH−
3. OH−; NH4+
4. NH3; H2O
5. OH−; H2O
Which adds the proton? That's the base.
Which donates the proton? That's the acid.
In the reversible reaction NH3 + H2O ⇌ NH4+ + OH−:
NH3 acts as a Bronsted-Lowry base because it accepts a proton (H+) to form NH4+.
H2O acts as a Bronsted-Lowry acid because it donates a proton (H+) to form OH−.
Therefore, the correct answer is:
4. NH3; H2O
To determine the Bronsted-Lowry acid and base in the reaction NH3 + H2O ⇌ NH4+ + OH−, we need to understand the concepts of acids and bases as defined by Bronsted-Lowry.
- A Bronsted-Lowry acid is a species that donates a proton (H+).
- A Bronsted-Lowry base is a species that accepts a proton (H+).
In this reaction, NH3 (ammonia) is a base because it can accept a proton to form NH4+ (ammonium ion). Therefore, NH3 acts as a Bronsted-Lowry base.
On the other hand, H2O (water) donates a proton to form OH− (hydroxide ion). Therefore, H2O acts as a Bronsted-Lowry acid.
From the given options, the correct answer is:
4. NH3; H2O