31 public questions tagged with this topic.
Alkynes follow the general formula C_nH_{2n-2, as they contain a triple bond. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.
Given: A compound has an empirical formula C₄H₉ and a molar mass of 114 g/mol. What is its molecular formula? (Atomic masses: C = 12, H = 1) Formula: Empirical mass = (4 × 12) + (9 × 1) = 48 + 9 = 57 g/mol. Substitution & Calculation: n = 114 / 57 = 2. Molecular formula = C₈H₁₈. Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.
Ref: NCERT Chemistry Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII)Topic: Mole concept, atomic structure, chemical formulas like H₂O, CO₂, CH₃CH₂NH₂ and periodic trends.
Given: A compound has an empirical formula Câ‚‚H₃Oâ‚‚ and a molar mass of 118 g/mol. What is its molecular formula? (Atomic masses: C = 12, H = 1, O = 16) These values define the system as per NCERT data. Formula: Empirical mass = (2 × 12) + (3 × 1) + (2 × 16) = 24 + 3 + 32 = 59 g/mol. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: n = 118 / 59 = 2. Molecular formula = Câ‚„H₆Oâ‚„. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kgâ»Â¹ Kâ»Â¹, m/s², 10â»âµ are properly used as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.
Given: A compound has an empirical formula CHâ‚‚O and a molar mass of 60 g/mol. What is its molecular formula? (Atomic masses: C = 12, H = 1, O = 16) These values define the system as per NCERT data. Formula: Empirical mass = 12 + 2 + 16 = 30 g/mol. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: n = 60 / 30 = 2. Molecular formula = Câ‚‚Hâ‚„Oâ‚‚. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kgâ»Â¹ Kâ»Â¹, m/s², 10â»âµ are properly used as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom and Periodicity, Topic: Mole concept, atomic models and periodic trends.
Maltose, made of two glucose units (each with 6 carbons), has a total of 12 carbon atoms (C₁2H₂2O₁1).
Ref: NCERT Class 12 Chemistry > Chapter 14: Biomolecules > Topic: Carbohydrates - Disaccharides and Glycosidic Linkage
Sucrose (C₁2H₂2O₁1) has 11 oxygen atoms, as indicated by its molecular formula.
Ref: NCERT Class 12 Chemistry > Chapter 14: Biomolecules > Topic: Carbohydrates - Disaccharides and Glycosidic Linkage
Butene (CH₂=CH-CH₂-CH₃) is an alkene with the formula C₄H₈, fitting CnH₂n.
Ref: NCERT Class 11 Chemistry > Chapter 9: Hydrocarbons > Topic: Alkenes - Preparation and Properties and Addition Reactions
Mass of C = (12/44) × 0.528 = 0.144 g. Mass of H = (2/18) × 0.108 = 0.012 g. Ratio C:H = (0.144/12)/(0.012/1) = 1:1. Empirical formula = CH.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Isomerism - Structural Isomerism - Chain Position Functional Metamerism
5 carbons (from 5 CO₂). CH₃CH₂CH₂CH₂CH₃ (pentane) has 9 σ (8 C-H, 1 C-C from single bonds), no π, and fits C₅H₁₂.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Fundamental Concepts - Reaction Mechanism - Fission and Reaction Intermediates
4 carbons (from 4 CO₂). Degree of unsaturation = 2 suggests two double bonds or one triple bond. CH₃C≡CCH₃ (but-2-yne, C₄H₆) fits with 2 π, 8 σ, and 4 CO₂.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Electronic Effects - Inductive Mesomeric Hyperconjugation and Resonance
Two π bonds suggest a diene. CH₂=CH-CH=CH₂ (buta-1,3-diene) has 2 π bonds and 7 σ bonds, fitting C₄H₆.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Classification and Nomenclature of Organic Compounds - IUPAC
Mass of C ≈ 0.84 g; mass of H = 0.14 g. Total = 0.98 g. Moles: C = 0.07, H = 0.14; ratio = 1 : 2; empirical formula = CH₂, mass = 14 g/mol. n = 98/14 = 7; molecular formula = C₇H₁₄.
Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Mole Concept and Molar Masses and Percentage Composition
