A dextrorotatory optically active alkyl halide undergoes hydrolysis by SN² mechanism. The resulting alcohol is

The SN2 (bimolecular nucleophilic substitution) reaction is characterized by a one-step mechanism where the nucleophile attacks the carbon atom bonded to the leaving group from the opposite side. This leads to inversion of configuration at the carbon center, often referred to as a "backside attack."

Key Points:

Optical Activity

• A dextrorotatory alkyl halide is optically active, meaning it can rotate plane-polarized light to the right (clockwise, denoted as "+").
• After the SN2 reaction, the configuration at the stereocenter inverts, producing a product with a flipped spatial arrangement.

Resulting Alcohol

• The inversion of configuration results in an alcohol that is also optically active, but the sign of rotation (whether it is dextrorotatory or levorotatory) depends on the structure of the molecule.
• The optical rotation is determined by the overall spatial arrangement of substituents, not merely the inversion itself. Hence, it cannot be predicted without additional information about the molecular structure.

Conclusion

• The product alcohol will be optically active but may be dextrorotatory (+) or levorotatory (-).
• The sign of rotation depends on the specific arrangement of atoms in the product and requires experimental measurement to determine.