Question

Which of the following statements is correct for optically active alkyl halides, upon reaction with nucleophiles?

$S _{ N } 1$		$S _{ N } 2$
(a)	Retention of configuration	Inversion of configuration
(b)	Racemisation	Inversion of configuration
(c)	Inversion of configuration	Retention of configuration
(d)	Racemisation	Retention of configuration

• A. a
• B. b
• C. c
• D. d

Answer 1

Answer: (B)

If an asymmetric carbon atom is not able to retain its spatial arrangement during a chemical reaction is known as inversion. Which occurs during $S _{ N } 2$ reaction. The nucleophile attacks the $C -X$ bond of an alkyl halide by the backside and so the configuration of molecule gets inverted.



While in $S _{ N }$ l mixture of both the types are obtained and is called racemisation.