Formic acid,which is a component of some insect venoms,has a K_a = 1.8 × 10^-⁴.What is the [H₃O⁺] in a solution that is initially 0.10 M formic acid,HCOOH?

Question

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The correct answer is A because the [H3O+] in a solution that is initially 0.10 M formic acid, HCOOH, can be calculated using the Ka expression: Ka = [H3O+][HCOO-] / [HCOOH]. Since Ka is 1.8 × 10^-4 and [HCOOH] is 0.10 M, we can assume that [H3O+] is approximately equal to [HCOO-]. Therefore, [H3O+] = sqrt(Ka * [HCOOH]) = sqrt(1.8 × 10^-4 * 0.10 M) = 4.2 × 10^-3 M.

Formic Acid,which Is a Component of Some Insect Venoms,has a Ka

Formic Acid,which Is a Component of Some Insect Venoms,has a K_a