a. Which reacts faster in an SN2 reaction?


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Verified step by step guidance

1. Identify the substrates involved in the SN2 reaction. SN2 reactions typically involve a nucleophile attacking an electrophilic carbon center, leading to the displacement of a leaving group.
2. Consider the steric hindrance around the electrophilic carbon. In SN2 reactions, less sterically hindered (less crowded) substrates react faster because the nucleophile can more easily approach and attack the carbon center.
3. Evaluate the nature of the leaving group. A good leaving group is one that can stabilize the negative charge after it departs. Generally, the better the leaving group, the faster the SN2 reaction.
4. Assess the strength and concentration of the nucleophile. Stronger and more concentrated nucleophiles can increase the rate of SN2 reactions by more effectively attacking the electrophilic carbon.
5. Compare the substrates based on the above factors to determine which one will react faster in an SN2 reaction.

Key Concepts

SN2 Reaction Mechanism

The SN2 (substitution nucleophilic bimolecular) reaction is a type of nucleophilic substitution where the nucleophile attacks the electrophile simultaneously as the leaving group departs. This concerted mechanism results in a single transition state and is characterized by a second-order reaction rate, dependent on the concentration of both the nucleophile and the substrate.

Steric Hindrance

Steric hindrance refers to the prevention of chemical reactions due to the spatial arrangement of atoms within a molecule. In SN2 reactions, substrates with bulky groups around the reactive center experience greater steric hindrance, making them less accessible to nucleophiles and thus slower to react compared to less hindered substrates.

Nucleophilicity

Nucleophilicity is a measure of a nucleophile's ability to donate an electron pair to an electrophile. Factors influencing nucleophilicity include charge, electronegativity, and solvent effects. Stronger nucleophiles, which are typically less electronegative and have a negative charge, will react faster in SN2 reactions due to their greater tendency to form bonds with electrophiles.