Question

The order of reactivity of the given haloalkanes towards nucleophiles is:

Options

• RI > RBr > RCl

• RCl > RBr > RI

• RBr > RCl > RI

• RBr > RI > RCl

Answer 1

RI > RBr > RCl

Explanation:

For a given alkyl group, the order of reactivity is \[\ce{<-[R - I  > R - Br > R - Cl > R - F][increasing bond energy]}\] decreasing halogen reactivity.

This order is determined by the carbon-halogen bond energy; the carbon-fluorine bond energy is the highest, so fluorides are the least reactive, while the carbon-iodine bond energy is the lowest, so iodides are the most reactive.