MolSynapse / Question bank / Organic Reaction Mechanisms IV: Elimination / E2 mechanism and anti-periplanar requirement

E2 mechanism and anti-periplanar requirement

36 questions on E2 mechanism and anti-periplanar requirement from the Organic Reaction Mechanisms IV: Elimination chapter: 8 NEET level, 14 JEE Main, 14 JEE Advanced. Each one opens with its answer and solution.

Practice this topic All Organic Reaction Mechanisms IV: Elimination topics

The rate law of an E2 reaction of bromoethane with ethoxide ion in ethanol is NEET level
2-Bromopropane is heated with alcoholic KOH. The main product is NEET level
In the preferred transition state of an E2 reaction, the dihedral angle between the C-H bond being broken and the C-X bond of the leaving group is NEET level
2-Bromobutane on heating with alcoholic KOH gives mainly NEET level
Trans-1-tert-butyl-4-chlorocyclohexane and cis-1-tert-butyl-4-chlorocyclohexane are each treated with NaOEt in ethanol. The tert-butyl group is so large that it... JEE Main level
2-Phenylethyl bromide C6H5CH2CH2Br and its analogue C6H5CD2CH2Br react with NaOEt in ethanol at the same temperature, and the first reacts about 7 times faster.... JEE Main level
Which order of the rate of E2 elimination with NaOEt in ethanol is correct for CH3CH2CH(X)CH3 (same base and temperature)? JEE Main level
2-Bromo-2-methylbutane is treated with (CH3)3COK in (CH3)3COH. The major alkene is JEE Main level
In 2-bromo-2,3-dimethylpentane, count every hydrogen atom attached to a carbon that is directly bonded to the carbon bearing bromine (the beta-hydrogens, i.e. t... JEE Main level
Which of the following statements about the E2 reaction of a secondary alkyl halide with a strong base is/are correct? JEE Main level
In which of the following reactions is the less substituted alkene (Hofmann product) the major one? JEE Main level
Menthyl chloride (2-isopropyl-5-methylcyclohexyl chloride in which Cl is trans to the isopropyl group; all three substituents are equatorial in its stable chair... JEE Advanced level
(1R,2S)-1,2-Dibromo-1,2-diphenylethane (the meso isomer) is treated with one equivalent of NaOEt in ethanol, and the E2 anti elimination of HBr takes place. The... JEE Advanced level
2,2-Dimethylcyclohexanol is treated with POCl3 in pyridine. The major alkene is formed by JEE Advanced level
cis-1-Bromo-2-methylcyclohexane and trans-1-bromo-2-methylcyclohexane are each treated with NaOEt in ethanol (E2). Which of the following is/are correct? JEE Advanced level
But-1-ene is treated with Br2 in CCl4. The product is then heated with three equivalents of NaNH2 in liquid ammonia, followed by water. The final organic produc... JEE Advanced level
2-Bromobutane reacts with NaOEt in ethanol by E2 to give only but-2-ene (cis + trans together) and but-1-ene. Treat each hydrogen separately: every H on C-3 lea... JEE Advanced level
Butan-2-amine is treated with excess CH3I to give the quaternary ammonium iodide, which is converted by moist Ag2O into the hydroxide and then heated (Hofmann e... JEE Advanced level
The rate law for an E2 reaction between an alkyl halide RX and a strong base B^- is: NEET level
In an E2 elimination from an acyclic alkyl halide, the preferred spatial arrangement of the beta C-H bond and the C-X bond is: NEET level
In the E2 reaction of a chlorocyclohexane derivative, the chlorine and the beta-hydrogen that is removed must be: NEET level
Among the butyl halides below, which has the best leaving group in E2 elimination? NEET level
The reaction of 2-bromopropane and of its hexadeuterated analogue (CD3)2CHBr with NaOEt in ethanol gives k_H/k_D approx 6.7. This large primary kinetic isotope ... JEE Main level
The elimination of tert-butyl bromide with NaOEt in ethanol follows rate = k[RX][EtO^-]. If [RX] is doubled and [EtO^-] is tripled at constant temperature, the ... JEE Main level
cis- and trans-1-tert-butyl-4-chlorocyclohexane are each treated with NaOEt in ethanol. The tert-butyl group is so large that it stays equatorial in both. Which... JEE Main level
Which statements about the E2 mechanism are correct? JEE Main level
2-Bromobutane is treated with the following species at the same concentration, temperature and solvent (ethanol). Which causes the fastest E2 elimination? JEE Main level
Count every hydrogen atom that is on a carbon atom directly bonded to the carbon bearing bromine (beta-hydrogens) in 2-bromo-2,3-dimethylbutane, (CH3)2CBr-CH(CH... JEE Main level
trans-1-Bromo-2-methylcyclohexane is heated with NaOEt in ethanol. The major alkene is: JEE Main level
Neomenthyl chloride is the diastereomer of menthyl chloride in which, in the more stable chair, chlorine is axial while the isopropyl (on C2) and methyl (on C5)... JEE Advanced level
cis-1-Bromo-2-methylcyclohexane is heated with NaOEt in ethanol. The major alkene and the reason are: JEE Advanced level
meso-1,2-Dibromo-1,2-diphenylethane, PhCHBr-CHBrPh (1R,2S), undergoes E2 with KOH in ethanol to remove one HBr. The product is 1-bromo-1,2-diphenylethene in whi... JEE Advanced level
trans-1-Bromo-4-tert-butylcyclohexane and cis-1-bromo-4-tert-butylcyclohexane react with NaOEt in ethanol; the tert-butyl group stays equatorial. Which statemen... JEE Advanced level
For the reaction of a secondary alkyl bromide with a strong base in ethanol, which observations point to an E2 mechanism rather than E1? JEE Advanced level
The diaxial conformer of trans-1-chloro-2-methylcyclohexane (Cl and CH3 both axial) is the reactive conformer for E2. How many beta C-H bonds in this conformer ... JEE Advanced level
Under identical conditions (NaOEt/EtOH, same temperature) the E2 elimination of 2-phenylethyl bromide, PhCH2CH2Br, is much faster than that of 1-bromopropane, C... JEE Advanced level