Which alkyl halide has maximum reactivity?

The order of alkyl halide reactivity is RI>RBr>RCl>RF.

Explanation

Alkyl halides also called haloalkanes or halogenoalkanes are chemical compounds that are often derived from alkanes that contain one or more halogens. Alkyl halide or haloalkanes are formed by the replacement of hydrogen atoms in an aliphatic hydrocarbon by halogen atoms (Fluorine, chlorine, bromine or iodine). They can also be produced from any organic parents such as alkanes, alkenes, or alcohols and carboxylic acids. Generally, alkyl halides contain hydrogen atoms attached to the sp³ hybridized carbon atom of alkyl groups.

Reactivity

Nucleophilic substitution reaction is a class of organic reactions where one nucleophile replaces another. The group which takes electron pair and displaced from the carbon is known as the “leaving group” and the molecule on which substitution takes place known as “substrate”. The leaving group leaves as a neutral molecule or anion.

• As per the leaving ability, the order is I>Br>Cl>F because the size of atoms gets bigger on moving from I to F.
• In terms of the existence of the C-X bond, which is a strongly polarised covalent bond due to the large difference in the electronegativities of carbon and halogen atoms, the high reactivity of alkyl halides can be clarified.

So the alkyl halide RI is more reactive to as compared any other alkyl halide.

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