Prelab Assignment 1. Review sections 15.1, 15.2, 15.3, and 15.6 in Kotz et al. 2
ID: 1031782 • Letter: P
Question
Prelab Assignment 1. Review sections 15.1, 15.2, 15.3, and 15.6 in Kotz et al. 2 Consider the reaction below at equilibrium. The solution is a bright royal purple color. 2 Mno,. (aq) + 5 car (aq) + 16 H. (aq) 2 Mn"(aq) + 10 co, (g) + 8 H2O(l) pvrple Note: The hydrated MnO, ion is purple. The hydrated Mn2" ion is pink. All of the other substances are colorless Use the observations provided and LeChatelier's principle to interpret the results of the following stresses placed upon the equilibrium system shown above: a.) The system at equilibrium is placed in a filter flask and attached to a vacuum aspirator. The purple color of the solution becomes lighter. b.) In another experiment, NaOH is added to the above system at equilibrium. The purple color of the solution becomes darker.Explanation / Answer
2.Ans:-
2MnO4^- (aq) + 5C2O4^-(aq) +16H^+(aq)-------> 2Mn^2+(aq) + 10CO2(g) + 8H2O(l).
observation
(a) Equilibrium shifts in forward direction, because pressure of CO2 reduced through vacuum. therefore intensity of purple colour of MnO4^- decreases.
(b) addition of NaOH in equilibrium solution shifts the equilibrium in backwards direction and therefore intensity of purple colour of MnO4^- increases. Addition of NaOH in solution decreases the concentration of H^+ and hence equilibrium shifts in backwards direction.
Note:- according to Le-Chatelier principle, if we decreases the concentration of reactants or increases the concentration of products,then equilibrium shifts in backwards direction as in b observation.
Similarly , if we will increases the pressure of equilibrium mixture then equilibrium will shifts in that direction which contains lesser no. of gaseous moles as in observation a .