Govt. Exams
Entrance Exams
hex-3-ene (CH3CH2CH=CHCH2CH3) has different groups on each carbon of the double bond, allowing cis-trans (E-Z) isomerism. Cyclohexane and alkanes have no double bonds, and 2-methylpent-2-ene is not a correct formula for C6H12.
Hydroboration-oxidation follows anti-Markovnikov's rule with syn addition. The OH adds to the less substituted carbon (primary), giving 1-butanol (butan-1-ol).
Aldol condensation produces a β-hydroxy carbonyl compound (aldol) initially, which can further dehydrate under heating to form an α,β-unsaturated carbonyl compound.
The methyl group (-CH3) is an alkyl group, which is an electron-donating group that activates the benzene ring and is ortho/para-directing in electrophilic aromatic substitution.
E1 elimination occurs in two steps: slow carbocation formation followed by fast deprotonation. The carbocation formation is the rate-determining step.
Tollens test detects aldehydes. Benzaldehyde contains an aldehyde group (-CHO) and will be oxidized to benzoate ion, giving a positive test (silver mirror).
Markovnikov's rule states that in addition to unsymmetrical alkenes, the hydrogen adds to the carbon with more hydrogen atoms, and the addendum to the carbon with fewer hydrogens, forming the more stable carbocation intermediate.
SN1 proceeds through carbocation formation. Tertiary carbocations are most stable (hyperconjugation and inductive effects), followed by secondary, then primary.
The molecule has two chiral centers (carbons bearing Br and OH). Each chiral center can have R or S configuration, giving 2² = 4 possible stereoisomers (diastereomers and enantiomers).
In the Kolbe carboxylation of phenols, CO2 is directly incorporated into the aromatic ring ortho to the hydroxyl group under high temperature and pressure with alkali, forming salicylic acid derivatives.
