NCERT  ·  Chemistry  ·  Class XI  ·  Ch.9

Hydrocarbons
MCQ Master Series

Alkanes · Alkenes · Alkynes · Aromatic Hydrocarbons · Markovnikov's Rule

🔥 50 Questions
⏱ 38 min Suggested
📊 3 Tiers
🗂 5 Topics
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Question Intelligence

Quiz Analytics

A data-driven breakdown of all 50 questions by difficulty, exam origin and topic distribution.

📈 Distribution Overview

50
Total Questions
CBSE Board
23
JEE Level
18
NEET Level
9

🗂 Topic Coverage

Alkanes: Prep. & Properties
22%
Alkenes: Prep. & Markovnikov
24%
Alkynes: Prep. & Acidity
20%
Aromatic Hydrocarbons & Benzene
22%
Combustion & Isomerism
12%
23
CBSE Board
18
JEE Level
9
NEET Level
Conceptual Framework

Key Concept Highlights

6 foundational pillars that power every question in this quiz. Understand these, and the answers follow naturally.

⛓️
Alkanes
Saturated hydrocarbons, CₙH₂ₙ₊₂. Prepared by Wurtz reaction, decarboxylation, and hydrogenation of alkenes/alkynes. Undergo free-radical halogenation (substitution) via initiation-propagation-termination steps.
🌿
Alkenes
Unsaturated, CₙH₂ₙ, contain one C=C double bond (sp² carbons). Prepared by dehydration of alcohols and dehydrohalogenation of alkyl halides. Undergo electrophilic addition reactions.
🎯
Markovnikov's Rule
In addition of HX to an unsymmetrical alkene, H adds to the carbon already bearing more hydrogens; the halogen goes to the more substituted carbon (via the more stable carbocation intermediate).
💥
Peroxide (Anti-Markovnikov)
In presence of peroxides, HBr adds opposite to Markovnikov's rule via a free-radical mechanism (Kharasch effect). Applies only to HBr, not HCl or HI.
🔺
Alkynes
Contain one C≡C triple bond (sp carbons), CₙH₂ₙ₋₂. Terminal alkynes show acidic character (≡C−H) and give precipitates with ammoniacal AgNO₃/Cu₂Cl₂ — a key identification test.
⬡
Aromatic Hydrocarbons
Benzene: planar, hexagonal, delocalised 6 pi-electron system with resonance stabilisation. Aromaticity requires cyclic, planar, fully conjugated systems obeying Huckel's rule. Undergo electrophilic aromatic substitution.
Pedagogical Value

Why MCQs Matter

Multiple-choice questions are not mere guessing games — they are the sharpest diagnostic tool available to a competitive exam aspirant.

~14%

of CBSE Class XI Chemistry — the single largest organic chapter by weightage

Quick Reference

Important Formula Capsules

6 must-memorise equations that surface repeatedly across CBSE and JEE papers.

Alkane General Formula
\[ C_nH_{2n+2} \]
Alkene General Formula
\[ C_nH_{2n} \]
Alkyne General Formula
\[ C_nH_{2n-2} \]
Wurtz Reaction
\[ 2RX + 2Na \xrightarrow{\text{dry ether}} R{-}R + 2NaX \]
Huckel's Rule
\[ \text{Aromatic if } \pi\text{-electrons} = 4n+2,\ n=0,1,2,\ldots \]
Complete Combustion
\[ C_xH_y + \left(x+\dfrac{y}{4}\right)O_2 \rightarrow xCO_2 + \dfrac{y}{2}H_2O \]
Learning Outcomes

What You Will Learn

By completing this quiz set you will have exercised all the following competencies.

01 Write preparation reactions of alkanes, alkenes, and alkynes from suitable precursors
02 Apply Markovnikov's rule and explain the peroxide effect for addition of HX to alkenes
03 Explain the free-radical mechanism of alkane halogenation
04 Distinguish terminal from internal alkynes using the ammoniacal AgNO₃/Cu₂Cl₂ test
05 Explain the structure, resonance, and stability of benzene using Huckel's rule
06 Predict the product and mechanism of electrophilic substitution in benzene
Exam Preparation

Strategy & Preparation Tips

5 evidence-based strategies to maximise your score in CBSE Boards and JEE.

Step 01
Markovnikov vs Anti-Markovnikov
Default: H goes to carbon with more H's (Markovnikov, ionic mechanism via stable carbocation). Only HBr + peroxide reverses this (anti-Markovnikov, free-radical). HCl and HI never show the peroxide effect — a favourite trap question.
Step 02
Free-Radical Steps by Heart
Initiation (homolysis by UV light), Propagation (chain reaction generating product + new radical), Termination (two radicals combine). Halogenation of methane is asked mechanism-wise almost every year.
Step 03
Alkyne Acidity Test
Only terminal alkynes (≡C−H) give a precipitate with ammoniacal AgNO₃ (white) or Cu₂Cl₂ (red). Internal alkynes give no precipitate — this distinguishes 1-butyne from 2-butyne in MCQs.
Step 04
Huckel's Rule Quick Check
Count pi electrons in the ring: must be planar, cyclic, fully conjugated, and equal to 4n+2 (2, 6, 10…). Benzene has 6 — classic aromatic. Cyclobutadiene has 4 — anti-aromatic, a common exception MCQ.
Step 05
Timed Practice Across Series
Hydrocarbons span four sub-topics in one chapter. Attempt this 50-question set in 38 minutes, alternating between alkane, alkene, alkyne, and aromatic questions to build series-switching speed.

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🎯 Knowledge Check

Chemistry — Hydrocarbons

50 Questions Class 11 MCQs
1
The general molecular formula of alkanes is:
2
Which of the following is the simplest alkane?
3
Which hydrocarbon contains a carbon-carbon double bond?
4
The general formula of alkenes is:
5
Which hydrocarbon contains a carbon-carbon triple bond?
6
The general formula of alkynes is:
7
Which of the following is an unsaturated hydrocarbon?
8
The hybridisation of carbon in methane is:
9
The bond angle in methane is approximately:
10
Which gas is commonly called marsh gas?
11
The major constituent of natural gas is:
12
Which hydrocarbon is used for artificial fruit ripening?
13
The IUPAC name of \(CH_3CH_2CH_3\) is:
14
The molecular formula of ethyne is:
15
Which hydrocarbon undergoes addition reactions readily?
16
The reaction of alkanes with chlorine in sunlight is called:
17
Which reagent decolourises bromine water?
18
Which reagent is used to distinguish saturated and unsaturated hydrocarbons?
19
Which hydrocarbon gives a sooty flame?
20
Benzene contains:
21
The hybridisation of carbon atoms in benzene is:
22
The shape of the benzene molecule is:
23
Which reaction is characteristic of benzene?
24
Which catalyst is used in hydrogenation of alkenes?
25
The product formed when ethene reacts with hydrogen is:
26
Which hydrocarbon is aromatic?
27
According to Hückel's rule, aromatic compounds contain:
28
Which hydrocarbon has the highest percentage of carbon?
29
Ethyne burns in oxygen to produce:
30
Which test distinguishes terminal alkynes?
31
Which of the following forms a white precipitate with ammoniacal cuprous chloride?
32
The acidity of terminal alkynes is due to:
33
Which hydrocarbon undergoes polymerisation to form polyethylene?
34
Ozonolysis of ethene gives:
35
Which reagent converts an alkene into a vicinal diol?
36
The major product of chlorination of methane is:
37
Which statement is correct regarding benzene?
38
Which intermediate is formed during nitration of benzene?
39
Which compound is most reactive towards electrophilic substitution?
40
Which compound is least reactive towards electrophilic substitution?
41
The correct order of bond strength is:
42
Which alkene shows geometrical isomerism?
43
Which alkene cannot exhibit geometrical isomerism?
44
Which hydrocarbon has the shortest carbon-carbon bond?
45
The reaction of acetylene with excess hydrogen in presence of Ni produces:
46
Which hydrocarbon gives only one monochloro derivative?
47
The heat of hydrogenation of benzene is much lower than expected because:
48
Which sequence correctly represents increasing acidity?
49
Which compound gives a positive Baeyer's test?
50
Which of the following statements is correct?
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ACADEMIA AETERNUM तमसो मा ज्योतिर्गमय · Est. 2025
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Hydrocarbons Class 11 MCQs with Answers | NCERT Chapter 9
Hydrocarbons Class 11 MCQs with Answers | NCERT Chapter 9 — Complete Notes & Solutions · academia-aeternum.com
The following **50 Multiple Choice Questions (MCQs)** are designed according to the latest **NCERT Class 11 Chemistry Chapter 9 – Hydrocarbons** syllabus and follow the conceptual approach adopted in CBSE examinations. The questions are arranged in a **progressive order of difficulty**, beginning with fundamental concepts such as the classification of hydrocarbons, molecular formulas, hybridisation, and nomenclature, before advancing to chemical properties, reaction mechanisms, aromaticity,…
🎓 Class 11 📐 Chemistry 📖 NCERT ✅ Free Access 🏆 CBSE · JEE
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Exam tip: Sharing chapter notes with your study group creates a reinforcement loop. Teaching a concept is the fastest path to mastering it.

Frequently Asked Questions

Hydrocarbons are organic compounds made up only of carbon and hydrogen atoms. They are classified into alkanes, alkenes, alkynes and aromatic hydrocarbons.

Hydrocarbons are classified into saturated hydrocarbons (alkanes), unsaturated hydrocarbons (alkenes and alkynes), and aromatic hydrocarbons based on the type of carbon-carbon bonds present.

Alkanes contain only single C-C bonds, alkenes contain at least one C=C double bond, and alkynes contain at least one C=C triple bond.

Benzene is highly stable because of resonance and the delocalisation of six p-electrons over the ring, making it an aromatic compound.

Benzene prefers electrophilic substitution because addition reactions destroy its aromatic stability, whereas substitution preserves the delocalised p-electron system.

Electrophilic substitution reactions involve the replacement of a hydrogen atom on the benzene ring by an electrophile. Common examples include nitration, halogenation, sulphonation and Friedel-Crafts reactions.

The substituent already attached to the benzene ring determines whether the incoming electrophile enters the ortho, meta or para position during electrophilic substitution.

Activating groups such as –OH, –NH2 and alkyl groups are generally ortho-para directing, while deactivating groups like –NO2, –COOH and –SO3H are meta directing. Halogens are an important exception because they are deactivating but ortho-para directing.

Hydrocarbons are one of the most important chapters in Organic Chemistry and form the basis for reaction mechanisms, named reactions and advanced organic chemistry questions in CBSE Board, JEE Main and NEET examinations.

These notes cover classification, nomenclature, preparation, physical and chemical properties, reaction mechanisms, electrophilic substitution, directive effects, solved examples, diagrams, NCERT solutions, exam tips and competency-based questions.

The MCQs cover alkanes, alkenes, alkynes, aromatic hydrocarbons, nomenclature, reactions, preparations, properties, and important NCERT concepts.

Yes, all questions are prepared according to the latest NCERT Class 11 Chemistry Chapter 9 syllabus and CBSE guidelines.

Yes, every MCQ is accompanied by the correct answer and a concise explanation to help you understand the concept.

Yes, these questions are highly useful for Class 11 school exams, CBSE annual examinations, and concept revision.

Absolutely. Many questions test fundamental concepts that are frequently asked in JEE Main and NEET examinations.

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    ACADEMIA AETERNUM तमसो मा ज्योतिर्गमय · Est. 2025
    Sharing this chapter
    Hydrocarbons Class 11 MCQs with Answers | NCERT Chapter 9
    Hydrocarbons Class 11 MCQs with Answers | NCERT Chapter 9 — Complete Notes & Solutions · academia-aeternum.com
    The following **50 Multiple Choice Questions (MCQs)** are designed according to the latest **NCERT Class 11 Chemistry Chapter 9 – Hydrocarbons** syllabus and follow the conceptual approach adopted in CBSE examinations. The questions are arranged in a **progressive order of difficulty**, beginning with fundamental concepts such as the classification of hydrocarbons, molecular formulas, hybridisation, and nomenclature, before advancing to chemical properties, reaction mechanisms, aromaticity,…
    🎓 Class 11 📐 Chemistry 📖 NCERT ✅ Free Access 🏆 CBSE · JEE
    Share on
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    X / Twitter
    Facebook
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    Threads
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    Email
    academia-aeternum.com/class-11/chemistry/hydrocarbons/mcqs/ Copy link
    💡
    Exam tip: Sharing chapter notes with your study group creates a reinforcement loop. Teaching a concept is the fastest path to mastering it.

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