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: (d) Cl-

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 and bases are proton acceptors. This framework helps classify substances based on their ability to donate or accept protons, which is essential for determining the strength of acids and bases.

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, while the acid that donates the proton forms its conjugate base. Understanding these pairs is crucial for identifying the strength of acids and bases, as strong acids have weak conjugate bases and vice versa.

Strength of Acids and Bases

The strength of an acid or base is determined by its ability to dissociate in water. Strong acids, like HCl, completely dissociate into ions, while weak acids, like acetic acid, only partially dissociate. Similarly, strong bases fully dissociate in solution, while weak bases do not. This concept is vital for classifying substances like Cl-, which is the conjugate base of a strong acid (HCl) and thus has negligible basicity.