If the ratio of acid to base in a buffer increases by a factor of 10,the pH of the buffer
A) increases by 1.
B) decreases by 1.
C) increases by 10.
D) decreases by 10.
E) remains unchanged.

Question

Quizplus · Accepted Answer

The pH of a buffer solution is determined by the pKa of the weak acid and the ratio of the conjugate acid-base pair. If the ratio of acid to base in the buffer solution increases by a factor of 10, then the concentration of the acid has increased 10-fold and the concentration of the base has decreased by a factor of 10. 
Since the pH of a buffer is determined by the ratio of the acid and base concentrations, this change in the ratio will cause the pH to shift towards the pKa of the weak acid. For example, if the pH was initially 7, it would decrease to 6, or if the pH was initially 8, it would decrease to 7. Therefore, the pH of the buffer would decrease by 1.

If the Ratio of Acid to Base in a Buffer