Which of the following is a Bronsted-Lowry base? Select one: CHa b. HCN NH3 d. Clz None of the above are Bronsted-Lowry bases
The Correct Answer and Explanation is:
The correct answer is c. NH3.
Explanation:
The Bronsted-Lowry definition of acids and bases is based on proton (H+) transfer. According to this theory:
- A Bronsted-Lowry acid is a substance that donates a proton (H+).
- A Bronsted-Lowry base is a substance that accepts a proton (H+).
Let’s break down each of the options:
- CH₄ (Methane): This molecule is not a Bronsted-Lowry base. It neither donates nor accepts protons. Methane is chemically stable and does not readily participate in proton transfer.
- HCN (Hydrogen Cyanide): This molecule contains a hydrogen atom, but it behaves as an acid under Bronsted-Lowry theory, not a base. It can donate a proton (H⁺) to form the cyanide ion (CN⁻). Therefore, it is a Bronsted-Lowry acid, not a base.
- NH₃ (Ammonia): Ammonia is a Bronsted-Lowry base because it has a lone pair of electrons on the nitrogen atom. It can accept a proton (H⁺) to form NH₄⁺ (ammonium ion). In aqueous solutions, ammonia readily accepts protons to form ammonium ions.
- Cl₂ (Chlorine gas): Chlorine gas does not have the ability to accept or donate protons. It is neither a Bronsted-Lowry acid nor a base. Chlorine typically participates in redox reactions, but not proton transfer.
Therefore, NH₃ is the only substance that qualifies as a Bronsted-Lowry base in this list, as it can accept a proton.
In summary, ammonia (NH₃) is a Bronsted-Lowry base because it can accept a proton to form NH₄⁺, which makes it fit the base definition in this theory.
