Chemistry

Problem

A buffer is prepared by mixing

50.0\,\text{mL}

of 0.20 M HA with

35.0\,\text{mL}

of 0.20 M NaA. The measured pH of the resulting solution is 3.65. What is the

pK_a

of HA? a)

3.50

4.01

3.81

3.65