Abuffer can only minimize changes in h⁺ levels over a portion of the ph scale, called the buffering of the buffer.

Zone.

Explanation:

A buffer which is a blend of a weak acid and its conjugate base or vice versa is meant to resist pH changes i.e. H+ levels over a portion of pH scale when an acid or base is added to it. This level up to which a buffer can resist pH change or H+ change is know as buffering zone of that buffer.

For example:

Acetate buffer can resist a pH change between 3.76 to 5.76 on pH scale.

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