Arrange the halogens `F_(2),Cl_(2),Br_(2),I_(2)`, in order of their increasing reactivity with alkanes.

Options

A. `I_(2) lt Br_(2) lt Cl_(2) lt F_2`
B. `Br_(2) lt Cl_(2) lt F_(2) lt I_(2)`
C. `F_(2) lt Cl_(2) lt Br_(2) lt I_(2)`
D. `Br_(2) lt I_(2) lt Cl_(2) lt F_(2)`

Answer

A

Explanation

Rate of reaction of alkanes with halogens is `F_(2) gt Cl_(2) gt Br_(2) gt I_(2)`
Alkane react with `F_2` is vigorously and with `I_2` the reaction is too slow that it requires a catalyst. It is because of high electronegativity of fluorine. Reactivity decreases with decreases in electronegativity and electronegativity decreases down the group