Question

1. At 25 °C, how many dissociated H+ ions are there in 327 mL327 mL of an aqueous solution whose pH is 11.65?

2. Write the balanced equation for each reaction. Phases are optional.

The carbonate ion (CO2−3)(CO32−) acts as a Brønsted base with water.

3. The carbon-containing product from the first reaction acts as a Brønsted base with water.

The carbon-containing product from the second reaction decomposes into carbon dioxide gas and water.

4. The carbon-containing product from the second reaction decomposes into carbon dioxide gas and water.

5. The Ka of propanoic acid (C2H5COOH)(C2H5COOH) is 1.34×10−5.1.34×10−5. Calculate the pH of the solution and the concentrations of C2H5COOHC2H5COOH and C2H5COO−C2H5COO− in a 0.265 M0.265 M propanoic acid solution at equilibrium.

pH=

C2H5COOH=

C2H5COO=

6. A monoprotic weak acid, HAHA, dissociates in water according to the reaction

HA(aq)+H2O(l)−⇀↽−H3O+(aq)+A−(aq)HA(aq)+H2O(l)↽−−⇀H3O+(aq)+A−(aq)

The equilibrium concentrations of the reactants and products are [HA]=0.110 M[HA]=0.110 M, [H3O+]=2.00×10−4 M[H3O+]=2.00×10−4 M, and [A−]=2.00×10−4 M[A−]=2.00×10−4 M. Calculate the KaKa value for the acid HA.

7. Write the balanced equation for the ionization of the weak base pyridine, C5H5NC5H5N, in water, H2OH2O. Phases are optional.

Answer 1