CN  ChemNexa

Hydrocarbons WBCHSE Class 11 MCQ & Practice Questions

Practice Hydrocarbons MCQs for WBCHSE Class 11 Chemistry with answers, explanations, chapter revision and related ChemNexa mock tests.

Register Free for Full Chemistry Practice

Hydrocarbons Revision Guide for WBCHSE Class 11 Chemistry

Hydrocarbons is part of WBCHSE Class 11 Chemistry preparation. A strong revision plan should combine concept review with exam-style questions so that definitions, relationships, calculations and exceptions are recalled accurately.

Use the sample MCQs on this page to check understanding, then attempt the related ChemNexa tests for broader practice. When an answer is wrong, review the explanation and return to the underlying concept before attempting another set.

Important Topics

  • Core definitions and principles
  • Important equations or relationships
  • Common applications and examples
  • Frequently confused concepts
  • Exam-style multiple-choice questions
  • Error review and targeted revision

Revision Tip

Create a one-page summary of trends, structures, reactions, exceptions and key terminology for Hydrocarbons, then test recall with mixed MCQs.

What to practise in Hydrocarbons

Concept Revision

Revise definitions, principles, equations, trends and core ideas from Hydrocarbons before attempting MCQs.

Exam-style MCQs

Use chapter-focused multiple-choice practice to improve accuracy, recall and application for WBCHSE Class 11 Chemistry.

Performance Practice

Attempt ChemNexa tests, review results and return to weak areas for another round of targeted revision.

Top 20 Hydrocarbons MCQs with Answers

These public questions are selected from the exact Hydrocarbons chapter, screened for topic relevance and deduplicated so repeated versions of the same MCQ are not shown publicly. Use them for quick revision, then sign in to attempt the complete test experience with more questions, results and performance review.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

1. The general formula of an acyclic saturated hydrocarbon is:

  • A. CnH2n-2
  • B. CnHn
  • C. CnH2n+2
  • D. CnH2n
Answer: C
Explanation: Open-chain alkanes follow CnH2n+2.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

2. The hybridisation of carbon in methane is:

  • A. dsp2
  • B. sp3
  • C. sp2
  • D. sp
Answer: B
Explanation: Methane has four equivalent sigma bonds and tetrahedral sp3 carbon.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

3. The approximate H-C-H angle in methane is:

  • A. 109.5°
  • B. 120°
  • C. 180°
  • D. 90°
Answer: A
Explanation: Tetrahedral geometry gives an angle of about 109.5°.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

4. The characteristic reaction of alkanes with halogens under UV light is:

  • A. Electrophilic addition
  • B. Nucleophilic addition
  • C. Hydrolysis
  • D. Free-radical substitution
Answer: D
Explanation: Alkane halogenation proceeds through a radical chain mechanism.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

5. The initiation step in chlorination of methane involves:

  • A. Formation of carbocation
  • B. Formation of carbanion
  • C. Homolytic cleavage of Cl2
  • D. Heterolytic cleavage of CH4
Answer: C
Explanation: Light causes Cl-Cl homolysis to chlorine radicals.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

6. Wurtz reaction is useful for preparing:

  • A. Aldehydes
  • B. Higher alkanes
  • C. Alkenes only
  • D. Alcohols
Answer: B
Explanation: Alkyl halides couple with sodium in dry ether to form higher alkanes.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

7. Decarboxylation of sodium carboxylate with soda lime gives an alkane having:

  • A. One carbon less
  • B. One carbon more
  • C. Same number of carbons always
  • D. Two carbons more
Answer: A
Explanation: Loss of the carboxyl carbon gives an alkane with one fewer carbon.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

8. Kolbe electrolysis of a carboxylate salt can produce:

  • A. Only an alcohol
  • B. Only an alkene
  • C. A ketone only
  • D. An alkane by radical coupling
Answer: D
Explanation: Anodic decarboxylation generates radicals that couple.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

9. The most stable conformation of ethane is:

  • A. Planar square
  • B. Boat
  • C. Staggered
  • D. Eclipsed
Answer: C
Explanation: Staggering minimises torsional strain.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

10. The eclipsed conformation of ethane is less stable because of:

  • A. Ionic repulsion
  • B. Torsional strain
  • C. Aromaticity
  • D. Hydrogen bonding
Answer: B
Explanation: Bonding electron pairs are aligned, increasing torsional repulsion.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

11. The general formula of an acyclic monoalkene is:

  • A. CnH2n
  • B. CnH2n+2
  • C. CnH2n-2
  • D. CnHn
Answer: A
Explanation: One C=C reduces hydrogen count by two relative to alkane.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

12. Carbon atoms of a C=C bond are generally:

  • A. sp3 hybridised
  • B. sp hybridised
  • C. d2sp3 hybridised
  • D. sp2 hybridised
Answer: D
Explanation: Each alkene carbon uses sp2 orbitals and one unhybridised p orbital.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

13. The C=C bond contains:

  • A. Two pi bonds
  • B. One pi bond only
  • C. One sigma and one pi bond
  • D. Two sigma bonds
Answer: C
Explanation: Double bonds consist of one sigma and one pi component.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

14. Restricted rotation about C=C is responsible for:

  • A. Tautomerism only
  • B. Geometrical isomerism
  • C. Chain isomerism only
  • D. Metamerism
Answer: B
Explanation: Rotation would require disruption of pi overlap.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

15. Ethene decolourises bromine solution because it undergoes:

  • A. Addition
  • B. Substitution only
  • C. Elimination
  • D. Condensation
Answer: A
Explanation: Bromine adds across the carbon-carbon double bond.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

16. Hydrogenation of an alkene produces:

  • A. An alkyne
  • B. An aromatic compound
  • C. A carboxylic acid
  • D. An alkane
Answer: D
Explanation: H2 adds across C=C, saturating it.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

17. Markovnikov's rule predicts addition of HX to an unsymmetrical alkene such that H adds mainly to carbon with:

  • A. Higher atomic mass
  • B. Aromatic character
  • C. More hydrogens already attached
  • D. Fewer hydrogens always
Answer: C
Explanation: The usual orientation corresponds to formation of the more stable carbocation intermediate.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

18. Peroxide effect is classically observed in addition of:

  • A. HF
  • B. HBr
  • C. HCl
  • D. HI
Answer: B
Explanation: In presence of peroxides HBr can add by a radical anti-Markovnikov pathway.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

19. Ozonolysis of an alkene is useful for locating:

  • A. Position of the double bond
  • B. Only carbon-carbon single bonds
  • C. Halogen atoms
  • D. Hydrogen bonds
Answer: A
Explanation: Cleavage products reveal the carbon skeleton around C=C.

WBCHSE Class 11 Chemistry · Hydrocarbons · Very Hard

20. Cold dilute alkaline KMnO4 converts an alkene mainly into:

  • A. Alkane
  • B. Alkyne
  • C. Aromatic ring
  • D. Vicinal diol
Answer: D
Explanation: Baeyer's reagent oxidises C=C to a glycol under mild conditions.

Login to Start Full Test

Hydrocarbons Practice Tests

Hydrocarbons Frequently Asked Questions

How should I prepare Hydrocarbons for WBCHSE Class 11 Chemistry?

Revise the core concepts first, make a short list of important relationships or exceptions, and then solve chapter-focused MCQs while reviewing every error.

How can ChemNexa help with Hydrocarbons practice?

This page provides public sample questions and links to published ChemNexa tests so you can combine quick revision with structured practice.

What should I do after getting an MCQ wrong?

Identify whether the mistake came from a concept gap, calculation, unit, sign, wording or memory error, review that point, and then attempt a similar question again.

Continue with another chapter to build connected concepts and strengthen your overall Chemistry preparation.

Continue WBCHSE Class 11 Chemistry

View all WBCHSE Class 11 chapters and testsBrowse all Chemistry PracticeCreate a free account