The document defines acids as donors of H+ ions and bases as acceptors of H+ ions. It states that after an acid donates an H+ ion, its conjugated base is left behind, and after a base accepts an H+ ion, its conjugated acid is formed. It then gives examples of acids and bases in two reactions, identifying the conjugated acid/base pairs in each.

1. an acid is a donor of H+. After an acid releases H+, the leftover becomes its conjugated base.
a base is an acceptor of H+. After a base accepts H+, it becomes its conjugated acid.
in the reaction a):
Cl- is a base (acepts H+) and HCl on the left side is its conjugated acid.
HF is an acid (donates H+) and F- is its conjugated base
in the reaction b):
NH4+ is an acid and NH3 is its conjugated base
CN- is a base and HCN is its conjugated acid
Solution
an acid is a donor of H+. After an acid releases H+, the leftover becomes its conjugated base.
a base is an acceptor of H+. After a base accepts H+, it becomes its conjugated acid.
in the reaction a):
Cl- is a base (acepts H+) and HCl on the left side is its conjugated acid.
HF is an acid (donates H+) and F- is its conjugated base
in the reaction b):
NH4+ is an acid and NH3 is its conjugated base
CN- is a base and HCN is its conjugated acid