11 NEET questions on Organic Chemistry — Basic Principles. A sample is shown below with full explanations; the rest are available free after signing up.
Sodium nitroprusside gives a blood-red colour with sulphide ion, so the test is really a test for sulphur in the sodium fusion extract. Of the four, only methionine contains sulphur — leucine, threonine and serine do not.
Source: NEET 2026 re-exam (21 June), Code 50, Q55
The ether is least polar — two alkyl groups flanking oxygen and no hydrogen bonding of its own. The ketone's carbonyl is more polar than that. The alcohol beats both because its O-H donates hydrogen bonds, and the carboxylic acid is the most polar of all, combining a carbonyl with an O-H. So A < C < B < D.
Source: NEET 2026 re-exam (21 June), Code 50, Q89
Cis-trans isomerism needs restricted rotation plus two different groups on each of the two restricted centres. Pent-1-ene is a terminal alkene, so one doubly bonded carbon carries two hydrogens. 2-Methylhex-2-ene has two methyl groups on the same alkene carbon. In 1,1-dimethylcyclopropane both methyls sit on one ring carbon. Only 1,2-dimethylcyclohexane has one methyl and one hydrogen on each of two ring carbons, so the methyls can be on the same face or opposite faces.
Source: NEET 2025 (4 May), Code 45, Q58