understand and use the terms conjugate acids and bases, defineconjugate acid–base pairs and identify these pairs in reactions

Sure, let's break it down:

1. Conjugate Acids and Bases: In an acid-base reaction, an acid donates a proton (H+) and a base accepts a proton. The species that remains after the acid has donated a proton is known as the conjugate base of that acid. Similarly, the species that is formed after the base has accepted a proton is known as the conjugate acid of that base.

2. Conjugate Acid-Base Pairs: A conjugate acid-base pair consists of two substances related to each other by the donating and accepting of a single proton. The acid is the proton donor and the base is the proton acceptor. For example, in the reaction of ammonia (NH3) with water, ammonia (NH3) acts as a base by accepting a proton from water to form its conjugate acid, ammonium (NH4+), and water acts as an acid to form its conjugate base, hydroxide (OH-).

3. Identifying Conjugate Acid-Base Pairs in Reactions: To identify these pairs in a reaction, look for two species that differ only by one proton. The species that has one more proton is the acid, and the one with one less proton is the base. For example, in the reaction H2O + NH3 ⇌ OH- + NH4+, the conjugate acid-base pairs are H2O/OH- and NH4+/NH3.