Relevant Titles

1. Carbon & Silicon Compounds — CBSE Class 11 MCQs (NCERT-Based)

2. CBSE Class 11 Chemistry Quiz: Carbon and Silicon Compounds — 30 Practice Questions

3. Chapter 11 p-Block Elements MCQs: Carbon & Silicon Compounds — Answers & Explanations

4. NCERT-Aligned MCQs for Class 11: Carbon, Silicon, SiO₂ and Related Compounds

5. CBSE Board Prep: Practice Test on Carbon and Silicon Compounds (Class 11 Chemistry)

Introduction

CBSE Class 11 Chemistry MCQs on Carbon and Silicon Compounds are essential for mastering Chapter 11 (The p-Block Elements) and for confidence in CBSE board exam preparation. This NCERT-aligned practice set focuses on the chemistry and bonding of key compounds — from CO₂ and carbonate chemistry to SiO₂, silicones and organosilicon reagents — and highlights differences in catenation, multiple bonding tendencies, and oxide behavior. Each question is crafted to test conceptual understanding and application: predicting oxidation states, interpreting bonding (e.g., metal–carbonyl interactions, Si–O networks), and identifying reactions such as hydrolysis of SiCl₄ or the reducing action of carbon at high temperature. Answers include short, clear explanations so students can correct misconceptions immediately. Chemical notation is formatted for WordPress (for example C₆₀, SiO₂, H₂O) to ensure accurate display. Use this timed MCQ set to simulate exam conditions, identify weak areas, and reinforce NCERT concepts — a focused way to boost accuracy and score in Class 11 Chemistry.

Sample MCQs (with answers and explanations)

Q1. Which of the following is the main structural unit of silicate minerals?
A) CO₃²⁻
B) SiO₄⁴⁻ tetrahedron
C) SiCl₄ monomer
D) CH₄ molecule
Answer: B — SiO₄⁴⁻ tetrahedron
Explanation: Silicates are built from SiO₄⁴⁻ tetrahedra that link via shared oxygen atoms to form chains, sheets or 3D frameworks; this underpins rock and glass structures.

Q2. Which statement correctly contrasts carbon and silicon bonding?
A) Both form stable multiple (double/triple) bonds equally easily.
B) Carbon readily forms stable C=C/C≡C bonds; silicon less readily forms Si=Si and prefers Si–O single bonds and networks.
C) Silicon forms aromatic rings like carbon commonly.
D) Carbon cannot form long chains (catenation).
Answer: B
Explanation: Carbon readily forms multiple bonds and extensive catenation. Silicon favors single Si–Si and especially Si–O bonds, giving extended silicate networks rather than stable Si=Si double bonds.

Q3. Which reaction shows hydrolysis of silicon tetrachloride?
A) SiCl₄ + 2H₂O → SiO₂ + 4HCl
B) SiCl₄ + H₂ → Si + HCl
C) SiCl₄ + NaCl → no reaction
D) SiCl₄ is inert to water
Answer: A
Explanation: SiCl₄ hydrolyses vigorously to give silicon dioxide (or silicic acid) and hydrochloric acid; this is a characteristic reaction of chlorosilanes.

Q4. Which carbon species acts as a strong ligand donating a lone pair to metals (forms metal carbonyls)?
A) CO
B) CO₂
C) CH₄
D) C₆₀
Answer: A — CO
Explanation: Carbon monoxide donates a lone pair from carbon to metal centers to form stable metal carbonyl complexes (e.g., Fe(CO)₅), and also accepts back-donation into its π* orbitals.

Q5. Why is SiO₂ a poor conductor of electricity while graphite (a carbon allotrope) conducts well in-plane?
A) SiO₂ has delocalized π-electrons, graphite does not
B) SiO₂ is ionic, graphite is covalent
C) SiO₂ is a 3D covalent network with no free electrons; graphite has delocalized π-electrons in sp² layers enabling conduction parallel to sheets
D) Both conduct equally well
Answer: C
Explanation: SiO₂ forms an insulating 3D network with all electrons localized in bonds. Graphite’s sp²-layered structure provides delocalized π-electrons that move freely within layers, causing electrical conductivity.