Adding acetate ion produces a change in the color of the indicator. Watch Video-le where a drop of methyl orange is added to each of two 3-mL samples of 0.1 M CH3COOH (acetic acid). The 1 M Na CH3COO (sodium acetate) is added a few drops at a time (with mixing) to one of the samples. The effect on the dissociation of acetic acid that is produced by adding sodium acetate is called the common ion effect. Specify the color after adding the sodium acetate and whether the reaction shifts toward the formation of HIn or toward the formation of In-. Explain how the acetate ion perturbs the methyl orange equilibrium (i. e. explain how it changes the concentration of one of the reactants or products in the methyl orange equilibrium reaction, therefore leading to a shift) by drawing the changes with arrows on the reaction(s) or writing them below. (1 point) After addition of sodium acetate Color change Chemical changed in the vertical rxn. Vertical reaction shift Chemical changed in the horizontal rxn. Horizontal reaction shift.