Question

If Ka for acetic acid is 1.78*10^-5, the pKa of acetic acid is _________

(a) 0.475

(b) 4.75

(c) 2.5

(d) 0.25

I had been asked this question in an interview.

This key question is from Enzyme Kinetics Fundamentals in chapter Enzyme Kinetics Fundamentals of Enzyme Technology

Answer 1

Correct choice is (b) 4.75

Best explanation: pKa is given by pKa = -log10[Ka]

pKa = -log10[1.78*10^-5] = – [-4.75] = 4.75.