Question

Define and give an equation to illustrate each of the following substances: a. a conjugate base b. a conjugate acid

Short answer

A conjugate base is A⁻ formed from HA. A conjugate acid is BH⁺ formed from B.

Step-by-step solution

- Define Conjugate Base

A conjugate base is the species that is formed when an acid donates a proton (H⁺) in a chemical reaction. It is called a 'base' because it can accept a proton in the reverse reaction.

- Provide Equation for Conjugate Base

The general equation for an acid (HA) donating a proton to form its conjugate base (A⁻) can be written as: \[ HA \rightarrow H^+ + A^- \]

- Define Conjugate Acid

A conjugate acid is the species that is formed when a base accepts a proton (H⁺) in a chemical reaction. It is called an 'acid' because it can donate a proton in the reverse reaction.

- Provide Equation for Conjugate Acid

The general equation for a base (B) accepting a proton to form its conjugate acid (BH⁺) can be written as: \[ B + H^+ \rightarrow BH^+ \]

Key concepts

Acid-Base Reactions

Acid-base reactions are fundamental concepts in chemistry. These reactions involve the transfer of a proton (H⁺) from an acid to a base. Understanding how proton transfer works is essential in grasping how acids and bases interact.
Think of an acid as a proton donor. When an acid loses a proton, it forms a conjugate base. Conversely, a base can accept a proton, transforming into a conjugate acid. This relationship helps us understand the reversible nature of these reactions.
For instance, let’s consider the reaction between hydrochloric acid (HCl) and water (H₂O). The equation can be written as:

Chemical Equations

Chemical equations are shorthand representations of chemical reactions using symbols and formulas. They show the reactants (substances going into the reaction) and the products (substances formed by the reaction). In acid-base reactions, these equations reveal how proton transfer occurs.
A typical acid-base reaction equation involves an acid (HA) and a base (B). Let's break down the notation used in these equations:

Proton Transfer

Proton transfer is the crux of acid-base reactions. During the reaction, acids lose protons, and bases gain them. This transfer process can be visualized with the help of chemical equations.
For a clearer understanding, let’s look at an example using acetic acid (CH₃COOH) and water (H₂O):