Read the following passage and answer the questions based on it.

Aldehydes are generally more reactive than ketones in nucleophilic addition reactions due to steric and electronic reasons. Sterically, the presence of two large groups in ketones hinders the attack of nucleophile to carbonyl carbon than in aldehydes. Electronically, aldehydes are more reactive than ketones because two alkyl groups reduce the electrophilicity of the carbonyl carbon more effectively than in the former.

The order of reactivity of the given haloalkanes towards nucleophile is

$RI>RBr>RCl$

The correct answer is Option (1) → $RI>RBr>RCl$.

To determine the order of reactivity of haloalkanes (alkyl halides) towards nucleophiles, we need to consider several factors, including the bond strength of the carbon-halogen bond and the nature of the halogen atoms involved (Iodine (I), Bromine (Br), and Chlorine (Cl)).

Factors Affecting Reactivity of Haloalkanes

Bond Strength:

The carbon-halogen bond strength decreases as you go from C-Cl to C-Br to C-I.

Bond Strength Order: C-Cl > C-Br > C-I

This means that C-I bonds are weaker and break more easily than C-Br or C-Cl bonds. Consequently, haloalkanes with iodine will react more readily with nucleophiles because the C-I bond is easier to break.

Leaving Group Ability:

The ability of a leaving group to depart from the substrate is crucial in nucleophilic substitution reactions. A better leaving group leads to a faster reaction.

Leaving Group Ability Order: I⁻ > Br⁻ > Cl⁻

Iodide is a better leaving group compared to bromide and chloride due to its larger size and weaker bond with carbon, which favors the formation of the carbocation or intermediate.

Reactivity Order of Haloalkanes

Based on the bond strength and leaving group ability, the reactivity of haloalkanes towards nucleophiles follows this order: RI > RBr > RCl

Explanation of Each Option

RI > RBr > RCl: Correct. This follows the reactivity order based on the bond strength and leaving group ability.

RCl > RBr > RI: Incorrect. This suggests that RCl is more reactive than RBr and RI, which contradicts the leaving group ability and bond strength.

RBr > RCl > RI: Incorrect. This suggests that RBr is more reactive than RI, which is not true due to the weaker C-I bond and better leaving group ability of iodide.

RBr > RI > RCl: Incorrect. While RBr is more reactive than RCl, RI should be the most reactive due to the weakest C-I bond.

Conclusion

The correct order of reactivity of the given haloalkanes towards nucleophiles is: RI > RBr > RCl.

This reflects the fact that iodides are more reactive than bromides, which are more reactive than chlorides due to the factors discusse