Final answer:
Weak acids are effective buffer components due to their conjugate bases of reasonable strength which can resist pH change when combined with their salts, providing a high buffer capacity in solutions.
Step-by-step explanation:
Weak acids make better buffers than strong acids because they have conjugate bases of reasonable strength. This quality allows them to resist changes in pH when small amounts of acid or base are added to the solution.
A buffer solution typically includes a weak acid and its conjugate base; weak acids and their salts are better as buffers for pHs less than 7. The concept of buffer capacity is important in understanding why weak acids are more effective.
A buffer has a higher capacity when there is an equal amount of weak acid and its conjugate base. The conjugate base of a strong acid, on the other hand, is very weak and cannot reassociate with H+ to reform the acid, making it ineffective as a buffer.
For instance, a buffer solution of acetic acid and sodium acetate (CH3COOH + CH3COONa) exemplifies the use of a weak acid and its salt to create a stabilizing effect on the pH of the solution.
Another noteworthy point is that the higher the amount of the weak acid/conjugate base present in the solution, the higher the buffer capacity.
Therefore, buffers typically contain appreciable amounts of a weak conjugate acid-base pair to effectively minimize pH fluctuations upon the addition of other acids or bases.