Relevant Titles
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Hydrocarbons MCQs for CBSE Class 11 — NCERT-Aligned Practice Test
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Physical & Chemical Properties of Hydrocarbons: Class 11 MCQs
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CBSE Class 11 Chemistry: Top Hydrocarbons MCQs with Explanations
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Introduction
Hydrocarbons MCQs Class 11: Strengthen your command over the physical and chemical properties of hydrocarbons with this NCERT-aligned practice set tailored specifically for CBSE Class 11 students. This focused resource covers essential topics — general formulas (for example, alkanes C<sub>n</sub>H<sub>2n+2</sub>), types of isomerism, characteristic reactions (addition, elimination, substitution, oxidation), aromaticity and resonance, and key diagnostic tests such as bromine decolourization. Each question targets the exact learning outcomes specified in the NCERT syllabus to make your revision efficient and exam-relevant.
Designed for both timed practice and conceptual clarity, every MCQ comes with a concise explanation that highlights the principle behind the correct choice and why other options are incorrect. Use these Hydrocarbons MCQs Class 11 for chapter revision, classroom quizzes, or last-minute board preparation. Regular practice will improve speed, reduce careless errors, and deepen conceptual understanding — helping you approach the CBSE Class 11 Chemistry paper with confidence. Start practising now and track which subtopics need more focus.
Sample MCQs (with answers and short explanations)
Q1. Which is the general formula of alkenes?
A. C<sub>n</sub>H<sub>2n+2</sub>
B. C<sub>n</sub>H<sub>2n</sub> ← Correct
C. C<sub>n</sub>H<sub>2n-2</sub>
D. C<sub>n</sub>H<sub>n</sub>
Explanation: Alkenes contain one carbon–carbon double bond and follow the formula C<sub>n</sub>H<sub>2n</sub>. Alkanes are C<sub>n</sub>H<sub>2n+2</sub>, and alkynes are C<sub>n</sub>H<sub>2n-2</sub>.
Q2. Which test quickly decolorizes bromine water indicating an unsaturation?
A. Test with KMnO<sub>4</sub>
B. Iodoform test
C. Bromine water test ← Correct
D. Tollen’s test
Explanation: Bromine (Br<sub>2</sub>/aq) adds across C=C or C≡C bonds; unsaturated hydrocarbons (alkenes/alkynes) decolourize bromine water rapidly due to addition reaction.
Q3. Which hydrocarbon shows aromatic stability explained by Hückel’s rule?
A. Cyclohexane
B. Benzene ← Correct
C. 1,3-Butadiene
D. Ethane
Explanation: Benzene (C<sub>6</sub>H<sub>6</sub>) is aromatic with 6 π-electrons that satisfy Hückel’s (4n+2) rule (n=1), giving resonance stabilization and lower reactivity toward addition.
Q4. The product of complete combustion of ethane, C<sub>2</sub>H<sub>6</sub>, is:
A. CO and H<sub>2</sub>O
B. CO<sub>2</sub> and H<sub>2</sub>O ← Correct
C. C and H<sub>2</sub>O
D. CO<sub>2</sub> only
Explanation: Complete combustion of hydrocarbons yields carbon dioxide and water: C<sub>2</sub>H<sub>6</sub> + 3.5 O<sub>2</sub> → 2 CO<sub>2</sub> + 3 H<sub>2</sub>O.
Q5. Which reagent converts an alkene into a vicinal diol (syn addition)?
A. Cold, dilute KMnO<sub>4</sub> ← Correct
B. HBr
C. H<sub>2</sub>/Pd
D. Br<sub>2</sub> (in inert solvent)
Explanation: Cold, dilute KMnO<sub>4</sub> oxidizes alkenes to give vicinal (adjacent) diols by syn hydroxylation. H<sub>2</sub>/Pd hydrogenates alkenes to alkanes; HBr and Br<sub>2</sub> give addition products but not diols.