Question

1.00 liter solution contains 0.31 M acetic acid and 0.40 M sodium acetate. If 0.100 moles of calcium hydroxide are added to this system, indicate whether the following statements are true or false. (Assume that the volume does not change upon the addition of calcium hydroxide.)

_______ A. The number of moles of CH3COOH will decrease.
_______ B. The number of moles of CH3COO- will decrease.
_______ C. The equilibrium concentration of H3O will decrease.
_______ D. The pH will decrease.
_______ E. The ratio of [CH3COOH] / [CH3COO-] will remain the same.

Answer 1

The answer is the explanation.

Step-by-step explanation:

The acetic acid, CH3COOH, reacts with calcium hydroxide, Ca(OH)2, producing acetate ion, CH3COO- and water as follows:

2CH3COOH + Ca(OH)2 → 2CH3COO- + 2H2O + Ca²⁺

That means the moles of acetic acid decrease whereas the moles of acetate ion are increased. The ratio of [CH3COOH] / [CH3COO-] is different.

As a base is added, the concentration of H3O+ decreases increasing the pH.

That means:

TRUE A. The number of moles of CH3COOH will decrease.

FALSE B. The number of moles of CH3COO- will decrease.

TRUE C. The equilibrium concentration of H3O will decrease.

FALSE D. The pH will decrease.

FALSE E. The ratio of [CH3COOH] / [CH3COO-] will remain the same.