Calculate the pH of a 0.04 M solution of ascorbic acid (K_a1= 7.9 $\times$ 10^-5; K_a2is 1.6 $\times$ 10^-12).

Question

Quizplus · Accepted Answer

Ascorbic acid is a weak acid with a pKa value of 4.1. To calculate the pH of a 0.04 M solution of ascorbic acid, we need to first calculate the concentration of H+ ions in the solution.

Ka = [H+][C6H8O6-]/[C6H8O62-]

pKa = -log(Ka)

4.1 = -log([H+][C6H8O6-]/[C6H8O62-])

[H+] = [C6H8O6-] = sqrt(Ka*[C6H8O62-]) = sqrt((1.6*10^-12)*(0.04)) = 1.6*10^-7 M

pH = -log[H+] = -log(1.6*10^-7) = 6.8

Therefore, the correct answer is B) 2.8.

Calculate the PH of a 0 ×\times× 10-5; Ka2 is 1 ×\times×

Calculate the PH of a 0 $\times$ 10^-5; K_a2is 1 $\times$