Equilibrium Lab - Restoring Balance. The solubility of iodine increases because the position of equilibrium has shifted towards the triiodide side of the reaction. Addition of the reactants causes an increase in the product which is directly related t

Post Lab Questions

1. CoCl42- ions are present in this solution as they are blue colored and the color of the Cobalt Chloride solution was blue when we recorded the color and appearance of the solution.

2. Co(H2O)62+ ion was favored by the addition of water as it is pink colored and when we added water to the cobalt chloride solution, it became pink. This was because the amount of Co(H2O)62+ ions went up(more pink) to compensate or even out the change. Adding more products resulted in the position of the equilibrium to shift towards the reactant side making it favor the Co(H2O)62+ ions.

3. (a) CoCl42- ion is favored by the addition of hydrochloric acid and calcium chloride.

(b)  Cl- ion

 (c) When the stress (Chlorine from hydrochloric acid and calcium chloride) is added on the reactant side (more reactants), the pink color reduces and blue color increases. In other words, CoCl42- is favored to compensate for the change or minimize the stress.

4. A. Adding a species which appears on the right side of an equation will shift the equilibrium to   the left side of the equation.

 B. Adding a species which appears on the left side of an equation will shift the equilibrium to   the right side of the equation.

5. Since acetone attracts water molecules (decrease water molecules from the reaction) the reaction tries to create more water. Making more of the product, it naturally makes more of all the products which creates CoCl42- ions (blue in color), resulting in a blue color of the system of chemicals.

6. (a) Ag+ + Cl- → AgCl

(b) The concentration of Cl- ions decreased as chlorine ions from the reactant side reacted with silver ions.

(c) As the concentration of Cl- ions decreased when silver nitrate was added, the reaction naturally makes more of all the reactants which creates Co(H2O)62+ ions which are pink, resulting in a pink color of the system of chemicals.

7. (a) Removing or decreasing the concentration of a species which appears on the right side of an equation will shift the equilibrium to the right side of the equation.

(b) Removing or decreasing the concentration of a species which appears on the left side of an equation will shift the equilibrium to the left side of the equation.

8. When the solution was heated, CoCl42- ion (blue in color) was favored as the whole solution became dark blue. Co(H2O)62+ ion (pink in color) was favored when the solution was cooled as the whole solution became light pink in color.

Heat + Co(H2O)62+ + 4Cl- → CoCl42- + 6H2O

9. Since Equation 5 is endothermic, heat is required for the reaction to proceed, and increasing the temperature (adding heat) will cause the position of the equilibrium to shift towards the products (CoCl42- side) resulting in a pink color of the whole solution. Cooling the solution (taking away the heat) shifts the position of the equilibrium towards the reactants (Co(H2O)62+  side) resulting in a pink color of the whole solution.