Entrance Exams
Govt. Exams
Chromic acid oxidizes primary alcohols to carboxylic acids. The aldehyde is an intermediate which is further oxidized.
Both Tollens and Fehling reagents give positive test with aldehydes (silver mirror and red precipitate respectively) but not with ketones.
Tertiary alkyl halides form stable tertiary carbocations, making SN1 mechanism favorable.
AlCl3 is the standard Lewis acid catalyst for Friedel-Crafts alkylation. It activates the alkyl halide to form a carbocation, which then attacks the aromatic ring.
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.
When dicarboxylic acids (HOOC-R-COOH) react with diols (HO-R'-OH), ester bonds form between the carboxyl and hydroxyl groups, creating polyester polymers with repeating ester linkages.