Question

Answer the following questions: On a 10-fold dilution of a weak acid, the pH will ______________ . On a 10-fold dilution of a weak base, the pH will ______________. If one adds a very small amount of strong base to a buffered solution, the pH will _______________. Can you make a buffer using a strong acid

Answer 1

Answer:

i) increase

ii) decrease

iii) remain the same

iv) No, because it dissociates completely.

Explanation:

On a 10-fold dilution of a weak acid, the pH will increase because the concentration of hydrogen ions will decrease thereby increasing the pH to close to that of water.

On a 10-fold dilution of a weak base, the pH will decrease due to the removal of hydroxide ions from the solution. This results in the solution having a H closer to that of water.

If one adds a very small amount of strong base to a buffered solution, the pH will remain constant because a buffer solution acts to withstand any change to its pH on the addition of small quantities of either an acid or a base.

A buffer solution cannot be made with a strong acid because thy undergo complete dissociation. Therefore, any small addition of base or acid will result in very large changes in the pH of the solution. A buffer solution is made with a weak acid and its conjugate base or a weak base and its conjugate acid.