Question

Consider two buffer solutions. Buffer 1 consists of 0.50 M HA and 0.25 M KA, and Buffer 2 is made from 0.050 M HA and 0.050 M NaA. How do the pHs of these buffer solutions compare?

Select one or more:

a. The pH of Buffer 1 is twice the pH of Buffer 2.

b. The pH of Buffer 1 is half the pH of Buffer 2.

c. The pH of Buffer 1 is equal to the pH of Buffer 2.

d. The pH of Buffer 1 is 0.3 lower than the pH of Buffer 2.

e. Cannot be determined without the K_a values.

Answer 1

Ka will remain constant for a particular acid despite a change in concentration (all other conditions, such as temperature, held constant).

So in given buffers, both has same acid so Ka value will be same so pKa value will also be same because pKa = log Ka

By using Henderson-Hasselbalch Equation

You can calculate the pH of buffers and compare them.