The Strength of a Conjugate Acid or Base

When a strong acid such as HCl dissolves in water, it ionizes completely because its conjugate base (Cr) has essentially no affinity for the ion in solution. 

Because the chloride ion has no affinity for the ion, it does not act as a Bronsted base in water. 

If we dissolve a chloride salt such as NaCl in water, for example, the Cl ions in solution would not accept protons from the water  

The chloride ion, which is the conjugate base of a strong acid, is an example of a weak conjugate base. 

Now consider the case of a weak acid. When HF dissolves in water, the ionization happens only to a limited degree because the conjugate base, F, has a strong affinity for the H ion  

This equilibrium lies far to the left = 7.1 X 10 ). Because the fluoride ion has a strong affinity for the ion, it acts as a Brpnsted base in water. If we were to dissolve a fluoride salt, such as NaF in water, the F ions in solution would, to some extent, accept protons from water  

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