Question

D. KOH and NaOH are both strong bases but had different effects when added to the saturated sodium chloride. Explain the equilibrium principle that accounts for these observations. E. Adding acetone to saturated NaCl solution Acetone is referred to as being completely miscible in water, meaning that it mixes with water in any concentration and there is no saturation limit. Use this information to explain the chemical principle that accounts for the observation reported above. F. What conclusions can be drawn regarding how a saturated solution in equilibrium responds when stress is placed on that system?

Answer 1

D. When NaOH is added to saturated solution of NaCl, precipitation will take place for NaCl. Such precipitation will not happen when KOH is added to the solution. This is because when the solution is saturated with NaCl, addition of excess Na ion will disrupt the equilibrium. Therefore to again regain the equilibrium, according to Le Chatelier principle, some of the reactant will be formed which in this case solid NaCl. With KOH, since no common ion is available, such precipitation will not take place and system will remain in equilibrium.

E. When acetone is added to saturated NaCl solution, precipitation will take place.

In a saturated solution the ions will remain solvated by water. This makes the ions stable in water. Since the solution is saturated, there is no water available to solvate any other ion. Now if acetone is added in this solution, some of the water molecules will be required to solvate these molecules. Thus the molecules available for Na and Cl ions will not be sufficient anymore ane hence some of the Na and Cl ions will precipitate out of the solution.

F. When stress is applied on a saturtaed solution, some more solute will be able to dissolve in the solution. This is because the equilibrium structure will be broken under the stress and some of the solvent molecules will be available now to accommodate some more ions. Hence solubility will increase.