Stereochemical outcome of substitution on drawn chiral substrates

14 questions on Stereochemical outcome of substitution on drawn chiral substrates from the Organic Reaction Mechanisms III: Nucleophilic Substitution chapter: 3 NEET level, 5 JEE Main, 6 JEE Advanced. Each one opens with its answer and solution.

• The chiral secondary bromide shown (single enantiomer) reacts with NaI in dry acetone for a short time, by a clean S_N2 pathway. What is the stereochemical resu... NEET level, drawn structure
• The optically active tertiary bromide shown is shaken with water-acetone in the absence of base. What is the optical activity of the alcohol product? NEET level, drawn structure
• The chiral chloride shown reacts with a good nucleophile by the S_N2 mechanism. From which direction does the nucleophile attack the stereogenic carbon? NEET level, drawn structure
• The enantiopure bromide shown reacts with NaI in acetone (short reaction time, S_N2). A structure drawn without wedges represents the racemic mixture. Which str... JEE Main level, drawn structure
• The enantiopure alcohol shown is converted to its tosylate with TsCl and pyridine, and the tosylate is then treated with NaN3 in DMF (S_N2). What is the configu... JEE Main level, drawn structure
• The dibromide shown has unspecified configuration at both stereocentres, i.e. it is the mixture of all its stereoisomers. It reacts completely with excess NaCN ... JEE Advanced level, drawn structure
• The tertiary bromide shown (one diastereomer, single enantiomer) is hydrolysed in water-acetone by a pure S_N1 pathway. Which description of the tertiary alcoho... JEE Main level, drawn structure
• The tosylate shown (single enantiomer) is treated with NaCN in DMSO to give a nitrile by clean S_N2. What is the CIP descriptor of the product, and why? JEE Advanced level, drawn structure
• The cis-disubstituted cyclohexyl bromide shown is treated with NaN3 in DMF (clean S_N2 at the C-Br carbon). Which structure is the major product? JEE Main level, drawn structure
• The enantiopure bromide shown reacts by S_N2 with various nucleophiles in aprotic solvents. Select all correct statements. JEE Main level, drawn structure
• The enantiopure alcohol shown is subjected to four successive steps: (1) TsCl, pyridine; (2) NaBr, DMF; (3) NaOAc, DMF; (4) K2CO3 in methanol (cleaves the aceta... JEE Advanced level, drawn structure
• The enantiopure alcohol shown is converted to the tosylate (TsCl, pyridine), which is then treated with NaBr in DMF. Separately, the alcohol is treated with PBr... JEE Advanced level, drawn structure
• The bromide shown (two stereocentres, single stereoisomer) is treated with NaI in acetone for a short time. Substitution occurs only at the carbon bearing Br, b... JEE Advanced level, drawn structure
• The trans-substituted tosylate shown is treated with NaCN in DMSO (S_N2), and the resulting nitrile is then reduced with LiAlH4. Which structure is the final am... JEE Advanced level, drawn structure