Answer:
Increase; remain constant, remain constant; No; by adjusting the acid:base ratio of the buffer.
Step-by-step explanation:
On a 10-fold dilution of a weak acid, the pH will INCREASE and that is because strong acids are not found in buffers, therefore, diluting a strong acid reduces the amount of hydrogen ions,H^+ present, consequently increasing the pH.
On a 10-fold dilution of a buffered solution, the pH will REMAIN CONSTANT because diluting a buffer does not affect the pH of the buffer.
If one adds a small amount of strong base to a buffered solution, the pH will REMAIN CONSTANT because the buffer will equalize the strong base, however, the pH may increase just a little.
One can not make a buffer solution using a strong acid because Buffers are composed of a weak acid and its conjugate base or a weak base and its conjugate acid, and weak acids or bases only dissociate partially. Strong acids dissociate completely, they overpower the reaction and move the reaction to completion.
pH of a buffer solution can be adjusted using by adjusting the acid:base ratio of the buffer.