Organic Chemistry – Some Basic Principles and Techniques: NEET questions with solutions

Tests IUPAC nomenclature, the electronic displacement effects (inductive, resonance, hyperconjugation) that govern carbocation and reaction-intermediate stability, structural isomer counting, and purification technique selection. Most NEET marks are lost applying lowest-locant rules in the wrong order (multiple bonds before prefixes such as chloro-), or confusing which effect (inductive vs resonance) explains a given stability trend.

1. 1.A student draws (CH₃)₂CH–CH₂–CH₃ and is unsure whether it is a straight-chain or branched alkane. What is its correct IUPAC name?IUPAC nomenclatureEasySingle correct
2. 2.Two completely miscible organic liquids have boiling points differing by only 8 K. Which technique is most suitable for separating them?Purification techniquesEasySingle correct
3. 3.Among F, Cl, Br, and I, which halogen shows the strongest −I (electron-withdrawing inductive) effect when directly attached to a carbon…Inductive effectEasySingle correct
4. 4.Which of the following carbocations is the most stable: CH₃⁺ (methyl), CH₃–CH₂⁺ (ethyl, 1°), (CH₃)₂CH⁺ (isopropyl, 2°), or (CH₃)₃C⁺…Carbocation stabilityMediumSingle correct
5. 5.In the acetate ion, CH₃COO⁻, both carbon–oxygen bonds are experimentally found to be equal in length, intermediate between a typical C–O…ResonanceMediumSingle correct
6. 6.How many structurally isomeric alcohols (compounds containing an –OH group, excluding ethers) have the molecular formula C₄H₁₀O?IsomerismMediumSingle correct
7. 7.The Assertion (A) and Reason (R) below concern how far the inductive effect reaches along a carbon chain. Read them and choose the option…Inductive effectMediumAssertion–Reason
8. 8.Allyl chloride (CH₂=CH–CH₂–Cl) ionises to give the allyl cation, represented by the two resonance structures CH₂=CH–CH₂⁺ ↔ ⁺CH₂–CH=CH₂.…Resonance / carbocation stabilityHardSingle correct
9. 9.A five-carbon chain carries a C=C double bond and a chlorine atom: CH₃–CH=CH–CHCl–CH₃. The compound has no principal characteristic group…IUPAC nomenclatureHardSingle correct