number 3 please, the answer is pH 4.76 but i cant figure out how to get the pH I

Question

number 3 please, the answer is pH 4.76 but i cant figure out how to get the pH

In the laboratory, you dissolve 0.99 mol CH_3COO^- and (Na^+ salt) in 1 L H_2O. Complete the Uble below with the concentrations of each species. What is the predominant species in solution at equilibrium? What is the pH of the solution at equilibrium? In the laboratory, you dissolve 0.5 mol CH_3COOH and 0.5 mol CH_3COO^- (Na^+ salt)in 1 L H_2O. You measure the pH of the solution using a pH meter. What with the pH meter read? Explain.

Explanation / Answer

Ka of CH3COOH = 1.76*10^-5
Ka = [H+][CH3COO-]/[CH3COOH]
1.76*10^-5= x * (0.01-x)/(0.99-x)

Since Ka is small , x will be small and it can ignored as compared to 0.01 and 0.99
ABove expression thus becomes,
1.76*10^-5= x * (0.01)/(0.99)
x = 1.7*10^-3 mol

So,
at equilibrium:
[CH3COOH] = 0.99 M
[H+] = 1.7*10^-3 M
[CH3COO-] = 0.01 M
Predominant species will be CH3COOH
--------------------------------
pH = -log [H+]
= -log (1.7*10^-3)
= 2.76
Answer: pH is 2.76

Related Questions

Navigate

• Browse (All)
• Browse N
• Subjects

---

---

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