A titration of 200.0 mL of 1.32 M H₂A was done with 1.00 M NaOH.For the diprotic acid H₂A,K_a1 = 2.5 $\times$ 10^-⁵,K_a2 = 3.1 $\times$ 10^-⁹.Calculate the pH before any 1.00 M NaOH has been added.

Question

Quizplus · Accepted Answer

The pH before any NaOH is added is determined by the first dissociation of the diprotic acid H₂A. Using the formula for pH = -log[H⁺], where [H⁺] is calculated from the initial concentration of H₂A and its first dissociation constant (Ka1), the pH is approximately 2.24.

A Titration of 200 ×\times× 10-5,Ka2 = 3 ×\times× 10-9

A Titration of 200 $\times$ 10^-⁵,K_a2 = 3 $\times$ 10^-⁹