Which solution will have the lowest pH?

Question

a. 0.10 M HClO2, pKa = 1.96
b. 0.10 M HCN, pKa = 9.21
c. 0.10 M HF, pKa = 3.19
d. 0.10 M HClO, pKa = 7.538
e. 0.00010 M HCl

Does the lower the pka stronger the acid, means the lower the ph, so the answer is A?

Answer 1

Yes but you must account for HCl separately. Of the acids listed with a pKa value, HClO2 is the strongest. Then HCl has pH of 4 so A is correct.