Dibromoethane and potassium iodide react in methanol (the solvent) according to the equation: C2H4Br2 + 3KI → C2H4 + 2KBr + KI3 The initial rate of this reaction was determined in a series of experiments at 65 °C, giving the data below:Experiment [C2H4Br2] /mol L–1 [KI] /mol L–1 +(d[KI3]/dt) /mol L–1s–11 0.426 1.909 0.006272 0.426 2.864 0.009413 1.067 1.909 0.0157 a) Determine the order of the reaction with respect to C2H4Br2Multiple choice 1 Question 10123b) Determine the order of the reaction with respect to KIMultiple choice 2 Question 10123c) Determine the value of the rate constant and select the appropriate units for it.

a) To determine the order of the reaction with respect to C2H4Br2, we compare experiments 1 and 3 where the concentration of KI is constant. The concentration of C2H4Br2 is doubled (1.067/0.426 = 2.5) and the rate of the reaction is also approximately doubled (0.0157/0.00627 = 2.5). This suggests that the reaction is first order with respect to C2H4Br2.

b) To determine the order of the reaction with respect to KI, we compare experiments 1 and 2 where the concentration of C2H4Br2 is constant. The concentration of KI is increased by a factor of 1.5 (2.864/1.909 = 1.5) and the rate of the reaction is also increased by a factor of 1.5 (0.00941/0.00627 = 1.5). This suggests that the reaction is first order with respect to KI.

c) The rate constant can be determined using the rate law expression for a first order reaction: rate = k[C2H4Br2][KI]. From experiment 1, we can substitute the known values into this equation: 0.00627 = k(0.426)(1.909). Solving for k gives k = 0.00627/(0.426*1.909) = 0.0073 L/mol/s. The units for the rate constant for a second order reaction are L/mol/s.