Organic Chemistry: Some Basic Principles and TechniquesNEET MCQs with solutions
This chapter is the gateway to Organic Chemistry for NEET. It covers IUPAC nomenclature, isomerism (structural and stereo), electronic effects (inductive, resonance, hyperconjugation), reaction intermediates (carbocations, carbanions, free radicals) and purification techniques. NEET tests nomenclature, stability order of intermediates, and effect identification heavily.
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- 11 Chemistry
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Tap an option to check it. Questions from every NCERT topic in this chapter, from easy to hard.
Q1Important PYQ Mixed Concepts
Geometrical isomers of a compound differ primarily in their:
Not quite — the answer is C.
Geometrical isomers have identical atomic connectivity but differ in the spatial arrangement of groups around a restricted bond such as C=C. Position of functional group describes position isomerism; carbon chain length describes chain isomerism.
Q2Nomenclature
Which of the following is the correct basis for selecting the parent chain in IUPAC nomenclature?
Not quite — the answer is A.
The parent chain is the longest continuous carbon chain that includes the maximum number of multiple bonds (double/triple). Option B is wrong: substituent count is irrelevant to chain selection. Option C describes the locant rule, which applies after chain selection.
Q3Electronic Effects
The inductive effect is transmitted through which type of bond?
Not quite — the answer is A.
Inductive effect operates through sigma bonds via permanent polarization along the chain. Pi bonds and lone pairs are involved in resonance/electromeric effects, not inductive transmission.
Q4Grand Test
The correct IUPAC name of CH3–CH(CH3)–CH2–CH(CH3)2 is:
Not quite — the answer is B.
The longest continuous chain contains five carbons (pentane). Numbering from the end nearer the first branch gives methyl groups at C2 and C4. The correct name is 2,4-dimethylpentane. 3,4-dimethylpentane uses wrong numbering direction; 2,3-dimethylpentane places the second methyl incorrectly; 3-methylpentane ignores one methyl group.
Q5Mixed Revision
Which one of the following compounds can exist as cis-trans isomers?
Not quite — the answer is D.
For geometrical isomerism, each doubly-bonded or ring carbon must carry two different groups. 1,2-Dimethylcyclohexane satisfies this condition. 1-Pentene has CH2= at C1 (two identical H), so no geometrical isomerism. 2-Methylpropene has two identical methyl groups on C2, so no geometrical isomerism. 1,1-Dimethylcyclopropane has two identical methyls on the same ring carbon.
Q6Reaction Mechanism
Homolytic bond cleavage produces:
Not quite — the answer is A.
Homolysis splits a covalent bond equally — each atom retains one electron, forming two electrically neutral free radicals. Heterolysis produces ions by unequal electron pair transfer.
Q7Isomerism
Which of the following correctly defines isomers?
Not quite — the answer is A.
Isomers share identical molecular formulae but differ in structural arrangement or spatial orientation. Option B reverses the definition. Option C is wrong: isomers typically differ in physical/chemical properties. Option D is too narrow — isomers need not differ in chain length.
Q8General Introduction to Organic Chemistry
Which of the following best distinguishes organic compounds from inorganic compounds?
Not quite — the answer is A.
The defining feature of organic compounds is the presence of C–H bonds. Option B fails because inorganic compounds like CO₂ and CaCO₃ also contain carbon. Option C fails because many inorganic compounds (e.g., SiO₂) are also covalent.
Q9Tetravalency of Carbon and Hybridisation
Why does carbon form four covalent bonds rather than gaining or losing electrons?
Not quite — the answer is A.
Carbon has four valence electrons — gaining 4 electrons (C⁴⁻) or losing 4 (C⁴⁺) would require extreme energy. Sharing four electrons via covalent bonds completes the octet most efficiently. Option C is the trap — carbon's electronegativity is intermediate, not high enough to favour ionic gain.
Q10Classification of Organic Compounds
Which class of organic compounds is characterized by open carbon chains with no ring structure?
Not quite — the answer is B.
Aliphatic (acyclic) compounds have open-chain carbon skeletons with no ring. Carbocyclic compounds are a trap — they include rings (alicyclic + aromatic) but are often confused with aliphatic by students. Alicyclic are cyclic but non-aromatic.
Q11Purification of Organic Compounds
Which purification method is most suitable when two miscible liquids differ in boiling points by more than 25°C?
Not quite — the answer is A.
Simple distillation is used when the boiling point difference between two miscible liquids exceeds 25°C, allowing effective separation by a single vaporisation-condensation cycle. Fractional distillation (Option B) is needed when boiling points are close (< 25°C difference). Steam distillation (Option C) is for immiscible, heat-sensitive compounds.
Q12Qualitative Analysis
Which of the following correctly describes the test used to detect carbon and hydrogen in organic compounds?
Not quite — the answer is A.
Carbon and hydrogen are detected by heating the compound with dry CuO — carbon oxidises to CO2 (turns lime water milky) and hydrogen oxidises to H2O (turns anhydrous white CuSO4 blue). Option B detects halogens. Option D (Beilstein) also uses copper but detects halogens via flame colour, not CO2/H2O.
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Get RankUp on Google PlayQ13Quantitative Analysis
Which of the following correctly defines the molecular formula of an organic compound?
Not quite — the answer is B.
The molecular formula gives the actual number of each type of atom present in one molecule — e.g., C6H12O6 for glucose. The simplest ratio (Option A) defines the empirical formula. Three-dimensional arrangement (Option C) is structural/stereochemical information. Mass percentage (Option D) is used to derive the empirical formula, not the molecular formula itself.
Q14Reaction Intermediates
Which intermediate is formed in an SN1 reaction, and why does SN2 not proceed through the same intermediate?
Not quite — the answer is B.
SN1 proceeds stepwise — the leaving group departs first forming a carbocation intermediate, then the nucleophile attacks. SN2 is a concerted single-step mechanism with no intermediate at all — bond breaking and bond forming happen simultaneously. Option A and C are mechanistically incorrect for both reactions.
Q15General Introduction to Organic Chemistry
At room temperature, simple organic compounds predominantly exist as:
Not quite — the answer is B.
Simple organic compounds have weak van der Waals forces, so they exist as liquids or gases at room temperature. Option A is incorrect — most simple organic compounds are not crystalline solids; that property is typical of ionic inorganic compounds.
Q16General Introduction to Organic Chemistry
Which element forms the structural backbone of all organic compounds, and what unique property enables this?
Not quite — the answer is C.
Carbon's unique ability to form stable C–C bonds with itself (catenation) enables it to form long chains and rings, making it the backbone of all organic compounds. Silicon also shows catenation but forms far less stable chains, making it the key trap here.
Q17General Introduction to Organic Chemistry
Which of the following correctly states why ionic bonding is absent in most organic compounds?
Not quite — the answer is D.
In organic compounds, carbon bonds with elements of similar electronegativity (H, N, O), making electron transfer energetically unfavourable. Ionic bonds require a large electronegativity difference, which is absent between C and these elements. Option B is a trap — coordinate bonds are a type of covalent bond, not the primary explanation.
Q18General Introduction to Organic Chemistry
Which of the following correctly explains why most organic compounds are poor conductors of electricity?
Not quite — the answer is A.
Electrical conduction requires free ions or electrons. Most organic compounds are covalent and do not ionise in solution or produce mobile electrons, so they are poor conductors. Option D is a trap — hydrogen bonding with water is a property of some organic compounds but has no bearing on electrical conductivity.
Q19General Introduction to Organic Chemistry
Wöhler's synthesis of urea in 1828 was significant because it:
Not quite — the answer is B.
Wöhler synthesised urea (an organic compound) from ammonium cyanate (an inorganic compound) without any living system, disproving the vital force theory that held organic compounds could only be made by living organisms. Option D is a trap — polymerisation was not involved.
Q20General Introduction to Organic Chemistry
Which of the following best explains the low solubility of most organic compounds in water?
Not quite — the answer is C.
Most organic compounds are non-polar or weakly polar due to covalent bonding, while water is highly polar. "Like dissolves like" — the polarity mismatch causes low solubility. Option A is a trap — molecular mass affects rate of dissolution, not fundamental solubility.
Q21General Introduction to Organic Chemistry
Which of the following is correctly classified as an inorganic compound despite containing carbon?
Not quite — the answer is D.
CS₂ (carbon disulfide) contains carbon but has no C–H bonds and is conventionally classified as inorganic. CH₄, C₂H₅OH, and C₆H₆ all contain C–H bonds and are organic. Note: HCN and CO₂ are similarly classified as inorganic despite containing carbon.
Q22General Introduction to Organic Chemistry
Between non-polar organic molecules, which intermolecular force is primarily responsible for cohesion?
Not quite — the answer is A.
Non-polar molecules have no permanent dipole, so hydrogen bonding and dipole-dipole interactions are absent. London dispersion forces arise from temporary induced dipoles and are the only significant intermolecular force between non-polar organic molecules.
Q23General Introduction to Organic Chemistry
Carbon has a valency of four. Which of the following correctly explains why this tetravalency maximises the diversity of organic compounds?
Not quite — the answer is B.
Tetravalency means carbon can form 4 covalent bonds simultaneously with the same or different atoms (C, H, N, O, halogens), enabling single, double, and triple bonds and branched or straight chains. Option A is a trap — C⁴⁻ formation is energetically prohibitive; carbon shares, not gains, electrons.
Q24General Introduction to Organic Chemistry
Which of the following pairs is correctly identified as inorganic compounds containing carbon?
Not quite — the answer is C.
CO₂ and CaCO₃ are classical inorganic carbon compounds — they lack C–H bonds and fall outside the definition of organic compounds. CO is also inorganic; CH₃OH contains C–H bonds and is organic. Option D is a trap — C₆H₆ (benzene) is organic.
ELITE question · AIR under 50 level
This chapter has 277 ELITE questions for students aiming at the very top. They are only in the app.
Unlock ELITE questions in the appKey Organic Concepts
Quick revision: most questions in this chapter test these facts.
| Concept | Key Fact |
|---|---|
| IUPAC naming | Longest chain + substituents in alphabetical order + suffix for functional group |
| Inductive effect | −I (electron-withdrawing: −NO₂, −COOH); +I (electron-donating: −CH₃, −C₂H₅) |
| Resonance | Delocalisation of π electrons or lone pairs; stabilises the system |
| Hyperconjugation | No-bond resonance; more α-H atoms = more stable carbocation |
| Carbocation stability | 3° > 2° > 1° > CH₃⁺ (hyperconjugation + inductive effect) |
| Isomerism | Structural (chain, position, functional group, metamerism) + Stereo (geometrical, optical) |
What the app covers in this chapter
591 questions in total, each with a detailed explanation.
| Important PYQ Mixed Concepts | 99 |
| Nomenclature | 59 |
| Electronic Effects | 57 |
| Grand Test | 57 |
| Mixed Revision | 53 |
| Reaction Mechanism | 42 |
| Isomerism | 41 |
| General Introduction to Organic Chemistry | 40 |
| Tetravalency of Carbon and Hybridisation | 39 |
| Classification of Organic Compounds | 21 |
| Purification of Organic Compounds | 21 |
| Qualitative Analysis | 21 |
| Quantitative Analysis | 21 |
| Reaction Intermediates | 20 |
Questions students ask
Is Basic Organic Chemistry important for NEET?
Extremely — it is the foundation for all Organic Chemistry chapters. IUPAC nomenclature, electronic effects and carbocation stability are tested directly and needed for every reaction mechanism.
Which topics should I revise first?
Master IUPAC nomenclature rules, inductive and resonance effects, carbocation/carbanion stability orders, types of isomerism, and the relationship between hyperconjugation and stability.
How many questions from this chapter are on RankUp?
The RankUp app has 591 questions on Organic Chemistry: Some Basic Principles and Techniques, including 277 ELITE questions. Every question has a detailed explanation.
