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Organic Chemistry — Basic Principles and Techniques — Class 11 MCQs with Answers

Class 11 CBSE Chemistry · Chapter 8

90 practice questions · 30 Easy · 30 Medium · 30 Hard · Updated

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Practise the most important Class 11 CBSE Chemistry questions from Chapter 8, "Organic Chemistry — Basic Principles and Techniques". You get 9 timed quizzes made from 90 NCERT-based MCQs, with answers and explanations. The questions are split into 30 Easy, 30 Medium and 30 Hard. Warm up on the basics, then move on to the exam-level questions that top scorers in CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET, JEE Advanced and NEET UG get right.

To score well in "Organic Chemistry — Basic Principles and Techniques", focus on reactions, key concepts and careful numericals. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This helps you stay accurate when time is short, just as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.

Use this chapter for focused revision. Start with the Easy set to check your basics on Organic Chemistry — Basic Principles and Techniques, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 11 Chemistry mastery score. Try the 6 sample questions below: tap an option to see the answer and a worked explanation. Sign in free to start practising.

Organic Chemistry — Basic Principles and Techniques — important questions & MCQs with answers (Class 11 Chemistry)

6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.

0 of 6 answered

  1. Q1 of 6Easy

    Functional group −OH belongs to:

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    Answer: Alcohol

    Explanation: The suffix -ol marks the hydroxyl (−OH) functional group, so −OH is an alcohol, e.g. CH₃−OH is methanol. Mixing it up with −COOH (acid, -oic) is the common slip.

  2. Q2 of 6Easy

    Compounds with the same molecular formula but different structures are called:

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    Answer: Isomers

    Explanation: Same molecular formula, different arrangement of atoms — that's isomerism, e.g. C₄H₁₀ as n-butane or isobutane. Allotropes are different forms of one element, not compounds.

  3. Q3 of 6Medium

    IUPAC name of (CH₃)₃C-CH₂-CH₃:

    Structural formula: a carbon C bonded to four groups — a CH₃ on its left, a CH₃ above, a CH₃ below, and a CH₂ on its right that is bonded to a further CH₃: (CH₃)₃C – CH₂ – CH₃.

    Show answer

    Answer: 2,2-dimethylbutane

    Explanation: The longest chain through (CH₃)₃C-CH₂-CH₃ is 4 carbons (butane) with two methyls both on C2, giving 2,2-dimethylbutane. Naming it 2-methylpentane wrongly folds a branch carbon into the main chain.

  4. Q4 of 6Medium

    Butane and iso-butane are:

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    Answer: Chain isomers

    Explanation: Butane (n-C₄H₁₀) and isobutane (2-methylpropane) share formula C₄H₁₀ but differ only in how the carbon skeleton branches, making them chain isomers, not the same compound.

  5. Q5 of 6Hard

    A free-radical intermediate has:

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    Answer: An unpaired electron

    Explanation: A free radical such as •CH₃ carries one unpaired electron in an otherwise neutral species, generated by homolytic bond cleavage, which makes it highly reactive. It has no net charge, so charge-based options both misdescribe it.

  6. Q6 of 6Hard

    Which compound does NOT show geometrical isomerism?

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    Answer: (CH₃)₂C=CHCH₃

    Explanation: Geometrical isomerism needs two different groups on each doubly-bonded carbon; in (CH₃)₂C=CHCH₃ one carbon carries two identical CH₃ groups, so swapping them regenerates the same structure. CHCl=CHCl and CH₃CH=CHCl both do show cis/trans forms.

Organic Chemistry — Basic Principles and Techniques notes: key concepts (Class 11 Chemistry)

Organic chemistry begins with carbon's ability to catenate and form four bonds. This chapter sets the ground rules: IUPAC nomenclature, structural and stereo isomerism, sp/sp²/sp³ hybridisation, the electronic effects that steer reactivity, the reaction intermediates, and the core reaction types and purification methods.

Catenation & tetravalency
Carbon forms four covalent bonds and links to itself in long chains and rings (catenation), which is the source of organic molecules' huge diversity.
Hybridisation of carbon
sp³ is tetrahedral 109.5° (alkanes), sp² trigonal planar 120° (alkenes), sp linear 180° (alkynes); s-character rises sp³ < sp² < sp.
Three molecules showing the shapes of carbon's hybrid bonds. Top: methane, CH₄, sp³ carbon, tetrahedral: two C–H bonds in the page 109.5° apart, one wedge bond towards the viewer and one hashed bond behind. Middle: ethene, C₂H₄, sp² carbons joined by a double bond, all atoms in one plane with 120° between the bonds at each carbon (trigonal planar). Bottom: ethyne, C₂H₂, sp carbons joined by a triple bond, H–C≡C–H in a straight line, 180° (linear).
Sigma and pi bonds
A σ bond forms by head-on overlap and allows free rotation; a π bond forms by sidewise p-overlap, is weaker and locks geometry, blocking rotation.
IUPAC nomenclature
Name = locants + substituents (alphabetical) + root (longest chain) + suffix (principal functional group), numbered to give the lowest locant set.
Functional group & homologous series
A functional group fixes the chemistry; a homologous series differs by CH₂, shares a general formula, and grades smoothly in physical properties.
Structural isomerism
Same molecular formula, different connectivity: chain, position, functional-group, metamerism and tautomerism are the recognised sub-types.
The three chain isomers of pentane, all with the molecular formula C₅H₁₂ but with the carbon atoms connected differently. Top: pentane, a straight chain CH₃–CH₂–CH₂–CH₂–CH₃. Middle: 2-methylbutane, a four-carbon chain CH₃–CH(CH₃)–CH₂–CH₃ with a CH₃ branch on the second carbon. Bottom: 2,2-dimethylpropane, a central carbon bonded to four CH₃ groups.
Stereoisomerism
Same connectivity, different spatial arrangement: geometrical (cis–trans) from restricted C=C rotation, and optical isomerism arising from chirality.
Geometrical (cis–trans) isomers of but-2-ene, CH₃–CH=CH–CH₃. Left: cis-but-2-ene, the two CH₃ groups on the same side of the C=C double bond and the two H atoms on the other side. Right: trans-but-2-ene, the two CH₃ groups on opposite sides of the double bond. The atoms are connected the same way in both; they differ only in spatial arrangement, and the two forms do not interconvert because there is no rotation about the C=C bond.
Inductive effect
Permanent σ-bond polarisation from electronegativity difference; −I groups (−NO₂, −COOH) withdraw and +I groups (alkyl) donate, fading with distance.
The inductive effect along the chain CH₃–CH₂–CH₂–Cl (1-chloropropane). Chlorine is more electronegative, so the σ electrons of the C–Cl bond are pulled towards it: Cl carries δ−, the carbon next to it (C₁) δ+, the next carbon (C₂) a smaller charge δδ+, and the third carbon (C₃) a still smaller δδδ+. Arrowheads on the bonds point towards Cl. The effect weakens quickly with distance from the chlorine.
Resonance (mesomeric) effect
Delocalisation of π or lone-pair electrons over the framework; the true molecule is a hybrid, more stable than any single canonical structure.
Resonance in benzene. Top: the two Kekulé (canonical) structures I and II, each a hexagon of six carbons with three alternating double bonds, the double bonds in different positions; a double-headed resonance arrow joins them. Below: the resonance hybrid, a hexagon with a circle inside showing the six π electrons delocalised evenly over the whole ring. The real molecule is the hybrid, more stable than either canonical structure.
Hyperconjugation
Delocalisation of σ(C–H) electrons into an adjacent empty p-orbital or π system; more α-hydrogens give greater stability (no-bond resonance).
Electromeric effect
A temporary, complete π-electron shift that happens only while an attacking reagent is present and reverses fully once the reagent is removed.
Reaction intermediates
Heterolytic fission gives carbocations (3° > 2° > 1° > CH₃⁺) and carbanions; homolytic fission gives neutral free radicals — all short-lived.
The three reaction intermediates of carbon, each a carbon with three groups R. Left: a carbocation, C⁺, sp² hybridised and planar, with an empty p orbital (dashed lobes) above and below the plane; formed by heterolytic fission. Middle: a carbanion, C⁻, sp³ and pyramidal, carrying a lone pair of electrons; also from heterolytic fission. Right: a free radical, neutral carbon with one unpaired electron (a single dot), from homolytic fission. Carbocation stability: 3° > 2° > 1° > CH₃⁺.
Reagents & reaction types
Electrophiles seek electrons and nucleophiles donate them; the four core reactions are substitution, addition, elimination and rearrangement.
Purification techniques
Solids are purified by crystallisation and sublimation, liquids by simple/fractional/steam distillation, and mixtures resolved by chromatography.
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Organic Chemistry — Basic Principles and Techniques — FAQs

What are the key concepts in Class 11 Chemistry Organic Chemistry — Basic Principles and Techniques?+

Organic chemistry begins with carbon's ability to catenate and form four bonds. This chapter sets the ground rules: IUPAC nomenclature, structural and stereo isomerism, sp/sp²/sp³ hybridisation, the electronic effects that steer reactivity, the reaction intermediates, and the core reaction types and purification methods. Key ideas include Catenation & tetravalency, Hybridisation of carbon, Sigma and pi bonds, IUPAC nomenclature, Functional group & homologous series, Structural isomerism.

What does Class 11 Chemistry Chapter 8 (Organic Chemistry — Basic Principles and Techniques) cover on XamBaaz?+

It has 90 NCERT-based MCQs on "Organic Chemistry — Basic Principles and Techniques": 30 Easy, 30 Medium and 30 Hard. Together they make 9 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET, JEE Advanced and NEET UG.

Are these "Organic Chemistry — Basic Principles and Techniques" questions free to practise?+

Yes. Sign in with Google to practise "Organic Chemistry — Basic Principles and Techniques" free. Full unlimited access is ₹1,999/year. One year from the day you pay. You stay in Class 11 till 31 March; on 1 April your account moves up to Class 12 and the rest of your year carries over. No chapter is charged separately.

How should I revise "Organic Chemistry — Basic Principles and Techniques" for the exam?+

Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 9 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.

Are these "Organic Chemistry — Basic Principles and Techniques" MCQs available with answers?+

Yes. 6 sample questions are on this page with answers: tap an option, or "Show answer", to see the correct option and a step-by-step explanation. Sign in free with Google to start practising, with instant scoring.

Is there negative marking in the "Organic Chemistry — Basic Principles and Techniques" quizzes?+

Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip, the same negative marking as JEE Main, JEE Advanced and NEET UG. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.

What are the important questions from Organic Chemistry — Basic Principles and Techniques (Class 11 Chemistry)?+

The questions that matter most test Catenation & tetravalency, Hybridisation of carbon, Sigma and pi bonds, IUPAC nomenclature, Functional group & homologous series, Structural isomerism. This page shows 6 solved important MCQs with answers and explanations. Sign in to practise all 90 questions on the chapter as timed quizzes.

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Yes — Class 11 Chemistry Organic Chemistry — Basic Principles and Techniques has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.

Are there question answers and extra questions for Organic Chemistry — Basic Principles and Techniques (Class 11 Chemistry)?+

Yes. This page has 6 solved questions on Organic Chemistry — Basic Principles and Techniques, each with the correct answer and a short explanation. Sign in to practise all 90 questions on the chapter as timed quizzes.

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