E5 Le Chatelier's Principle (b) Weak Acid Base Indicator Equilibria (i) Describe the effects of adding... HCI to methyl orange HCl to phenolphthalein NaOH to methyl orange NaOH to phenolphthalein Interpret these effects in terms of the indicator equilibrium equation given below and Le Chtelier's principle Hin + H2O HO + In (c) Weak Acid Weak Base Equilibria (1) Complete the equation for the dissociation equilibrium of acetic acid in water. CH3 + H2O + Predict the direction of the shift in the above equilibrium when 1 M sodium acetate is added to 0.1 M acetic acid containing methyl orange indicator. Are the observed changes to the methyl orange indicator consistent with Le Chtelier's principle upon the addition of 1 M sodium acetate? Briefly explain. (ii) Complete the equation for the reaction of ammonia with water: NH3 + H2O + (iii) Describe any observed odor or color changes when you add the following to 0.1 M NH3(aq) containing phenolphthalein indicator: NH4Cl - HCI - Indicate in which direction, left(+) or right (), does each reagent above shift the equilibrium for the reaction of NH3 with water? Adding NH4C1 = adding HCl (iv) Explain clearly the shift indicated in the ammonia with water equilibrium using Le Chtelier's principle and the observed color change in the phenolphthalein indicator. When NH4Cl is added - When HCl is added - Start with the net ionic equation betv HCl and NH3 -8