Question

Experiment 8 Exercises Name 25 pts On the basis of your results in Part A classify the compounds you studied as electrolytes or nonelectrolytes. (7 pts) 2. Explain the effect of added water on the conductivity of glacial acetic acid. Write a balanced reaction between acetic acid and water (6 pts) 3. Which reacted more vigorously with the Mg, HCl or HC H:0? Explain any difference observed! (6 pts) 4. Write a balanced reaction between Ba(OH), and H.SO. Explain any observed change in conductivity (6 pts)

Answer 1

1. An electrolyte is any salt or ionizable molecule that, when dissolved in solution, will give that solution the ability to conduct electricity. This is because when a salt dissolves, its dissociated ions can move freely in solution. Electrolyte solutions are normally formed when a salt is placed into a solvent such as water.

Examples of electrolytes: Sodium chloride, nitric acid, chloric acid, hydrochloric acid, calcium chloride, potassium nitrate etc.

Non electrolytes are compounds that do not ionize at all in solution. Hence they do not conduct electricity

Examples: Urea, benzene, sugar, ethanol, chloroform, ether etc.

2. Acetic acid is a weak acid in water and hence it ionizes and donates protons to water molecule. Since ionization occur during addition of water to acetic acid, it conduct electricity and conductivity increases with increased addition of water. Eventually when the acetic acid solution becomes too dilute, the conductivity starts to fall.

CH₃COOH + H₂O ⇋ CH₃COO^- + H₃O⁺

3. When Mg reacts with HCl or CH₃COOH, fizzing is produced in the solution due to the evolution of H₂ gas.

Mg_(s) + 2HCl_(aq)⟶ MgCl_2(aq) + H_2(g)

Mg_(s) + CH₃COOH_(aq)⟶ (CH₃COO)₂Mg_(aq) + H_2(g)

Since HCl is more strong acid than acetic acid, Mg reacts with HCl more vigorously and evolve hydrogen easily.

4. Barium hydroxide reacts with sulfuric acid to form insoluble barium sulfate.

Ba(OH)₂ + H₂SO₄⟶ BaSO₄ + 2H₂O

Barium hydroxide is a strong base as well as a strong electrolyte. When sulfuric acid is as added barium sulfate is formed, which is little ionizable. As a result of this the number of ions in the solution decreases and hence the conductivity also decreases. With continued addition of sulfuric acid even after all the barium hydroxide is converted to barium sulfate, the additional sulfuric acid ionizes in solution and hence conductivity increases.