plz tell me the techniques on dealing with q's related to BUFFER CAPACITY.

Buffer capacity

The property of buffer solution to resist alteration in its pH value is known as buffer capacity. It has been found that if the ratio [Salt]/[Acid] or [Salt]/[Base] is unity, the pH of a particular buffer does not change at all. Buffer capacity is defined quantitatively as number of moles of acid or base added in one litre of solution as to change the pH by unity

Buffer capacity is maximum:

When [Salt] = [Acid], i.e., pH =pKafor acid buffer

When [Salt] = [Base], i.e., pOH =pKbfor base buffer under above conditions, the buffer is called efficient.