N2O4 2NO2, Kc = 4. This reversible reaction is studied graphically as shown in the given figure. Select the correct statement out of I, II and III. I : Reaction quotient has maximum value at point A II : Reaction proceeds left to right at a point when [N2O4] = [NO2] = 0.1 M III : Kc = Q when point D or F is reached :