Label each of the following as being a strong base, a weak base, or a species with negligible basicity. In each case write the formula of its conjugate acid, and indicate whether the conjugate acid is a strong acid, a weak acid, or a species with negligible acidity: (e) NH3.

Verified step by step guidance

1. Step 1: Identify the given species. In this case, we are given NH3, which is ammonia.
2. Step 2: Determine the basicity of the given species. NH3 is a weak base because it does not completely dissociate in water.
3. Step 3: Write the formula of its conjugate acid. The conjugate acid of a base is formed by adding a proton (H+) to the base. Therefore, the conjugate acid of NH3 is NH4+.
4. Step 4: Determine the acidity of the conjugate acid. NH4+ is a weak acid because it does not completely ionize in water.
5. Step 5: Summarize the findings. NH3 is a weak base and its conjugate acid NH4+ is a weak acid.

Key Concepts

Acid-Base Theory

Acid-base theory explains the behavior of acids and bases in chemical reactions. According to the Brønsted-Lowry theory, acids are proton donors, while bases are proton acceptors. This framework helps classify substances like NH3, which acts as a base by accepting protons to form its conjugate acid, NH4+.

Conjugate Acid-Base Pairs

A conjugate acid-base pair consists of two species that differ by the presence of a proton (H+). When a base accepts a proton, it forms its conjugate acid, and vice versa. For NH3, its conjugate acid is NH4+, which can be classified based on its strength as an acid, influencing the overall acid-base behavior.

Strength of Acids and Bases

The strength of acids and bases is determined by their ability to dissociate in water. Strong acids completely ionize, while weak acids only partially ionize. NH3 is a weak base because it does not fully accept protons, and its conjugate acid, NH4+, is also a weak acid, indicating that it does not fully dissociate in solution.