Entrance Exams
Govt. Exams
As alkyl chain length increases, the electron-donating effect of the alkyl group increases, destabilizing the conjugate base carboxylate ion. Thus, formic acid (no alkyl group) is most acidic.
SN2 is a one-step bimolecular mechanism where the nucleophile attacks from the back side of the carbon bearing the leaving group, resulting in complete (Walden) inversion of configuration.
K2Cr2O7 in acidic medium is a strong oxidizing agent that oxidizes primary alcohols first to aldehydes, then further oxidizes the aldehyde to carboxylic acids.
Cold dilute KMnO4 causes hydroxylation of alkenes to form vicinal diols via syn addition. 2-methylpropene forms 2-methylpropane-1,2-diol (geminal diol arrangement on same carbon after rearrangement).
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).