Which of the statements is/are true about the reactivity of halogenation of alkanes? The reactivity order is F2>Cl2>Br2>I2I. Lower the activation energy for the chain initiation step, more reactive is the halogen.II. Lower the activation energy for the first chain propagation step, more reactive is the halogen.III. More negative is the overall heat of the reaction ΔHr∘ of halogenation of alkane, more reactive is the halogen.fV. Lower the activation energy for the second chain propagation step, more reactive is the halogen.