100 mole of formic acid (or methanoic acid) is added to water, the final volume

Question

100 mole of formic acid (or methanoic acid) is added to water, the final volume being 1.00L o f solution. The K_a= 1.80 Times 10^-4 Write the balanced chemical equation for the equilibrium (use hydronium ion rather than hydrogen ion in the balanced equation.) find the equilibrium concentrations of each species (check 5% rule, but go ahead and use successive approximation to calculate concentrations to 3 sig figs) calculate the pH of the solution calculate the hydroxide concentration of the solution.

Explanation / Answer

a) HCOOH (aq) + H2O (l) <---> HCOO-(aq) + H3O+ (l)

b) at equilibrium [HCOOH] = 0.1-X , [HCOO-] = [H3O+] = X

Ka = [HCOO-][H3O+]/[HCOOH]

1.8x10^ -4 = X^2 / ( 0.1-X)

X = 0.00415 = [H3O+] [HCOO-] ,

[HCOOH] = 0.1-0.0041536 = 0.0959 M

c) pH = -log [H+] = -log ( 0.00415) = 2.38

d) [OH-] = 10^ -14 /[H+] = 10^ -14 / ( 0.00415) = 2.41 x 10^ -12 M

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.