Entrance Exams
Govt. Exams
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.
Grignard reagents are strong nucleophiles and strong bases. They readily abstract a proton from water, producing an alkane (R-H) and magnesium halide salt.
The C=O stretch of carbonyl compounds (aldehydes, ketones, carboxylic acids, esters) appears characteristically around 1700-1750 cm⁻¹ in IR spectrum.
H2SO4 protonates HNO3 to form H2NO3+, which loses water to generate the nitronium ion (NO2+), the actual electrophile in electrophilic aromatic substitution.
The longest carbon chain contains 4 carbons with the aldehyde group (CHO) at position 1. The hydroxyl group is at position 3, giving 3-hydroxybutanal.
SN2 reaction requires easy access to the carbon bearing the leaving group. Ethyl bromide (primary alkyl halide) has minimal steric hindrance and is highly reactive in SN2 reactions.