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Stereochemical outcomes of substitution

36 questions on Stereochemical outcomes of substitution from the Haloalkanes and Haloarenes chapter: 6 NEET level, 14 JEE Main, 16 JEE Advanced. Each one opens with its answer and solution.

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(R)-2-Bromobutane reacts with aqueous NaOH by a pure S_N2 mechanism. The product butan-2-ol is NEET level
Optically pure (R)-3-bromo-3-methylhexane is hydrolysed in a polar solvent by an S_N1 pathway. The 3-methylhexan-3-ol obtained is NEET level
A racemic mixture is optically inactive because NEET level
(S)-2-Bromo-1-chloropropane, CH3-CH(Br)-CH2Cl, reacts with KCN in DMSO by an S_N2 reaction in which only the C-Br bond reacts. The product, 3-chloro-2-methylpro... JEE Main level
(S)-Butan-2-ol is treated with SOCl2 in the presence of pyridine. The product is JEE Main level
cis-1-Bromo-4-methylcyclohexane reacts with aqueous NaOH under conditions where only S_N2 substitution occurs. The product is JEE Main level
Optically pure (R)-1-bromo-1-phenylethane is stirred in aqueous acetone, where the reaction proceeds by S_N1 through ion pairs. The 1-phenylethanol formed is JEE Main level
(S)-1-Bromo-2-methylbutane reacts with NaCN in DMSO by S_N2 at the CH2Br carbon. The product 3-methylpentanenitrile is JEE Main level
Optically pure (R)-2-iodobutane is left for a long time in dry acetone containing excess NaI. The optical activity of the solution will JEE Main level
Which of the following statements about the stereochemistry of substitution at a chiral secondary carbon are correct? JEE Main level
(R)-2-Bromobutane is treated with NaI in dry acetone to give X by S_N2. X is then treated with aqueous NaOH under conditions where only S_N2 occurs to give Y. T... JEE Advanced level
(S)-Butan-2-ol is treated with SOCl2 in the absence of a base to give A. A is then treated with NaI in dry acetone to give B by S_N2. The compound B is JEE Advanced level
Racemic cis-1-bromo-3-methylcyclohexane reacts with NaSH under conditions where only S_N2 substitution occurs at the carbon bearing Br. Which statements are cor... JEE Advanced level
1-Bromo-1,4-dimethylcyclohexane (either cis or trans) is hydrolysed in aqueous acetone by an S_N1 mechanism. Which statements are correct? JEE Advanced level
Optically pure (R)-2-halo compound reacts to give a product that is 70% inverted and 30% retained in spatial arrangement (an S_N1 reaction with partial ion-pair... JEE Advanced level
(S)-2-Bromobutane reacts with different nucleophiles by a pure S_N2 pathway. Which statements are correct? JEE Advanced level
(S)-Pentan-2-ol is converted into 2-chloropentane in two ways: with SOCl2 alone (route 1) and with SOCl2 in pyridine (route 2). Which statements are correct? JEE Advanced level
(R)-2-Bromo-1-chloropropane, CH3-CH(Br)-CH2Cl, is treated separately with CH3COOK in DMSO (giving A) and with KCN in DMSO (giving B), each by pure S_N2 at the C... JEE Advanced level
(R)-2-Bromobutane reacts with aqueous NaOH by a pure SN2 mechanism. The major product is NEET level
Optically pure (R)-3-bromo-3-methylhexane is hydrolysed in water by a pure SN1 pathway (ignore any small excess of inversion). The alcohol formed is NEET level
Walden inversion in an SN2 reaction means that NEET level
Optically pure (S)-2-iodobutane is stirred with NaI in dry acetone. Iodide exchange occurs by SN2 only. The optical activity of the solution gradually falls to ... JEE Main level
(R)-2-Chlorobutane reacts with sodium ethanoate in a polar aprotic solvent by a pure SN2 mechanism. The product, butan-2-yl ethanoate, is JEE Main level
(R)-Butan-2-ol is treated with SOCl2 alone, without pyridine (SNi mechanism with retention). The product is JEE Main level
(R)-Butan-2-ol is treated with SOCl2 in the presence of pyridine. The main product is JEE Main level
cis-1-Bromo-4-methylcyclohexane is treated with NaI in dry acetone and undergoes a single SN2 substitution at C-1. The product is JEE Main level
(S)-1-Bromo-2-methylbutane, BrCH2-CH(CH3)-CH2CH3, reacts with KCN in DMSO (SN2 at the CH2Br carbon). The product 3-methylpentanenitrile is JEE Main level
Assertion: SN1 hydrolysis of an optically active secondary alkyl halide often gives a product with a slight excess of the inverted enantiomer instead of a perfe... JEE Main level
(R)-2-Bromo-1-methoxypropane, CH3-CH(Br)-CH2-O-CH3, reacts with NaCN in DMSO by a pure SN2 mechanism at the stereocentre. The product is CH3-CH(CN)-CH2-O-CH3 (3... JEE Advanced level
(R)-Butan-2-ol is treated with SOCl2 and pyridine to give X. X is then treated with excess hydroxide under conditions of pure SN2 to give Y. Y is JEE Advanced level
Select the SN2 reactions in which the product has a CIP label opposite to that of the substrate. In each case the nucleophile replaces the halogen with inversio... JEE Advanced level
cis-1-Bromo-1,4-dimethylcyclohexane is hydrolysed in water by a pure SN1 mechanism (planar tertiary carbocation, water attacks either face). Select the correct ... JEE Advanced level
(R)-Butan-2-ol is converted into 2-halobutanes by the following methods. Select the correct statements about the main product. JEE Advanced level
Which of the following give an optically inactive product (ignore partial inversion in SN1; assume complete racemisation where an SN1 step is stated)? JEE Advanced level
A single enantiomer of cis-1-bromo-3-methylcyclohexane is treated with NaSH in DMF (pure SN2 at C-1). The product 3-methylcyclohexane-1-thiol is JEE Advanced level
(3R,4S)-3-Chloro-3,4-dimethylhexane undergoes hydrolysis in water by a pure SN1 mechanism (planar carbocation at C-3; C-4 is unaffected). The 3,4-dimethylhexan-... JEE Advanced level