For an endergonic reaction step, the Hammond postulate allows one to say that . For an endergonic reaction step, the Hammond postulate allows one to say that . the step is rate-determining since it has the smallest Ea the reaction containing this step is overall first order the transition state of the step resembles the products of the step the transition state is precisely symmetric with bond-breaking and bond-forming occurring to the same extent the transition state of the step resembles the reactants of the step

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.