Question

Arrange the halogens $F_2$, $Cl_2$, $Br_2$, $I_2$, in order of their increasing reactivity with alkanes.

• A. $I_2 < Br_2 < Cl_2 < F_2$
• B. $Br_2 < Cl_2 < F_2 < I_2$
• C. $F_2 < Cl_2 < Br_2 < I_2$
• D. $Br_2 < I_2 < Cl_2 < F_2$

Answer 1

Answer: (A)

Rate of reaction of alkanes with halogens is $F_2 > Cl_2 > Br_2 > I_2$.
Reactivity decreases down the group as the electronegativity of the halogen decreases down the group.