Answer in Organic Chemistry for ivynf #121974
April 21st, 2023
pH = pKa + log ([A] / [HA])
pH goes to 6.85
9.5 = 10.33 + log ([A] / [HA])
10.33 – 9.5 = log ([A] / [HA])
0.83 = log ([A] / [HA])
so using the new pH,
6.85 = pKa + 0.83
6.85 – 0.83 = pKa
pKa = 6.02
Answer: pKa = 6.02.