The Br0nsted-Lowry theory conjugate acid-base pairs

3 The Br0nsted-Lowry theory conjugate acid-base pairs 

In light of the above comments on the nature of H (aq), instead of representing the dissociation of HCl in water by Reaction (4.18), we might better represent it by 

From this viewpoint, we could consider an acid as a substance that can donate a proton to another molecule (rather than as a substance that releases free protons). 

The Arrhenius theory views all bases as substances that produce OH (aq) ions. However, acid-base type reactions can occur in non-aqueous solvents, in which OH (aq) cannot be present because there are no oxygen atoms in the system. For example, HCl reacts with pure liquid ammonia 

Since NH3 has eliminated the acid HCl, we could consider NH3 as a base. 

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