NCERT Class 11 Chemistry Important Questions: 100 One-Liner Questions and Answers

NCERT Class 11 Chemistry Important Questions: Important Questions and Answers

NCERT Class 11 Chemistry Important Questions: Mastering NCERT Class 11 Chemistry is crucial for students aiming to excel in board exams and competitive entrance tests like TS EAMCET, JEE Main, and NEET. The NCERT Class 11 Chemistry textbook serves as the foundation for understanding key concepts such as atomic structure, chemical bonding, thermodynamics, and organic chemistry. By focusing on NCERT Class 11 Chemistry important questions, students can prioritize high-weightage topics, enhance problem-solving skills, and build a strong conceptual base. This resource compiles essential questions directly from the NCERT textbook, designed to help students prepare effectively and achieve academic success.

Below are 100 one-liner questions and answers based on the NCERT Class 11 Chemistry textbook (English, 2023-24 edition).

1. What is the SI unit of amount of substance? Mole
2. What is the mass of one mole of carbon-12 atoms? 12 grams
3. What is Avogadro’s number? 6.022 × 10²³
4. What is the empirical formula of a compound with 40% C, 6.67% H, 53.33% O? CH₂O
5. What is the molecular formula of glucose if its empirical formula is CH₂O? C₆H₁₂O₆
6. What is the limiting reagent in a reaction? The reactant that gets consumed first
7. What is the law of conservation of mass? Mass of reactants equals mass of products
8. What is the law of definite proportions? A compound always contains elements in a fixed ratio by mass
9. What is Dalton’s atomic theory’s main postulate? Matter consists of indivisible atoms
10. What is the charge of an electron? -1.602 × 10⁻¹⁹ coulomb
11. Who discovered the electron? J.J. Thomson
12. What is the mass of a proton relative to an electron? 1836 times heavier
13. What is an isotope? Atoms with same atomic number but different mass numbers
14. What is the atomic number of carbon? 6
15. What is Bohr’s model’s key assumption? Electrons orbit the nucleus in fixed energy levels
16. What is the maximum number of electrons in n=2 shell? 8
17. What is Planck’s constant value? 6.626 × 10⁻³⁴ J·s
18. What is the de Broglie wavelength formula? λ = h / (mv)
19. What is Heisenberg’s uncertainty principle? Position and momentum cannot be measured simultaneously with precision
20. What is the shape of an s-orbital? Spherical
21. How many orbitals are in the p-subshell? 3
22. What is the Aufbau principle? Electrons fill orbitals in order of increasing energy
23. What is Hund’s rule? Electrons occupy degenerate orbitals singly before pairing
24. What is the electron configuration of sodium (Na)? 1s² 2s² 2p⁶ 3s¹
25. What is the Pauli exclusion principle? No two electrons can have identical quantum numbers
26. Who proposed the modern periodic table? Dmitri Mendeleev
27. What is the atomic radius trend across a period? Decreases from left to right
28. What is ionization energy? Energy required to remove an electron from an atom
29. What is electronegativity? Tendency of an atom to attract shared electrons
30. Which element has the highest electronegativity? Fluorine
31. What is the valency of oxygen in water? 2
32. What is a covalent bond? Bond formed by sharing of electrons
33. What is the shape of a water molecule? Bent
34. What is VSEPR theory used for? Predicting molecular geometry
35. What is the bond angle in methane (CH₄)? 109.5°
36. What is hybridization in CH₄? sp³
37. What is a sigma bond? Single covalent bond formed by head-on overlap
38. What is a pi bond? Bond formed by sideways overlap of p-orbitals
39. What is the dipole moment of CO₂? Zero (linear molecule)
40. What is hydrogen bonding? Attraction between H and electronegative atoms like O, N, F
41. What are the conditions for Boyle’s law? Constant temperature and amount of gas
42. What is Charles’ law? Volume of a gas is proportional to absolute temperature at constant pressure
43. What is the value of the gas constant R? 8.314 J/(mol·K)
44. What is Avogadro’s law? Equal volumes of gases at same T and P contain equal moles
45. What is the ideal gas equation? PV = nRT
46. What is Dalton’s law of partial pressures? Total pressure equals sum of partial pressures
47. What is the kinetic energy of one mole of an ideal gas? (3/2)RT
48. What is Graham’s law of diffusion? Rate of diffusion is inversely proportional to square root of molar mass
49. What is the critical temperature of a gas? Temperature above which it cannot be liquefied
50. What is van der Waals’ equation used for? Correcting ideal gas law for real gases
51. What is the first law of thermodynamics? Energy cannot be created or destroyed
52. What is enthalpy (H)? Heat content of a system at constant pressure
53. What is the formula for enthalpy change? ΔH = H_products – H_reactants
54. What is an exothermic reaction? Reaction that releases heat
55. What is Hess’s law? Enthalpy change is same regardless of reaction path
56. What is entropy (S)? Measure of disorder in a system
57. What is Gibbs free energy formula? ΔG = ΔH – TΔS
58. When is a reaction spontaneous? When ΔG is negative
59. What is the second law of thermodynamics? Entropy of an isolated system increases
60. What is the standard state temperature in thermodynamics? 298 K
61. What is chemical equilibrium? State where forward and reverse reaction rates are equal
62. What is Le Chatelier’s principle? System at equilibrium adjusts to minimize external changes
63. What is the equilibrium constant Kc? Ratio of product concentrations to reactant concentrations
64. What is the effect of increasing pressure on N₂ + 3H₂ ⇌ 2NH₃? Shifts equilibrium to the right
65. What is an acid according to Arrhenius? Substance that releases H⁺ ions in water
66. What is a base according to Bronsted-Lowry? Proton acceptor
67. What is the pH of a neutral solution at 25°C? 7
68. What is the formula for pH? pH = -log[H⁺]
69. What is a buffer solution? Solution that resists pH change
70. What is the solubility product (Ksp)? Product of ion concentrations in a saturated solution
71. What is a redox reaction? Reaction involving oxidation and reduction
72. What is oxidation? Loss of electrons
73. What is reduction? Gain of electrons
74. What is an oxidizing agent? Substance that accepts electrons
75. What is the oxidation number of oxygen in H₂O? -2
76. What is the purpose of balancing a redox reaction? Ensure conservation of mass and charge
77. What is the general formula of alkanes? CₙH₂ₙ₊₂
78. What is the functional group of alcohols? -OH
79. What is an alkene? Hydrocarbon with at least one double bond
80. What is the general formula of alkynes? CₙH₂ₙ₋₂
81. What is isomerism? Compounds with same molecular formula but different structures
82. What is the IUPAC name of CH₃CH₂OH? Ethanol
83. What is a functional group? Atom or group responsible for chemical properties
84. What is the product of complete combustion of hydrocarbons? CO₂ and H₂O
85. What is the main source of alkanes? Petroleum
86. What is environmental chemistry? Study of chemical processes in the environment
87. What is the primary component of air pollution? Particulate matter
88. What is photochemical smog? Smog formed by sunlight reacting with pollutants
89. What is the greenhouse effect? Trapping of heat by gases like CO₂ in the atmosphere
90. What is acid rain caused by? SO₂ and NOₓ reacting with water
91. What is the ozone layer’s role? Protects Earth from UV radiation
92. What is the chemical formula of ozone? O₃
93. What are CFCs? Chlorofluorocarbons, ozone-depleting compounds
94. What is BOD in water pollution? Biochemical Oxygen Demand
95. What is eutrophication? Nutrient enrichment leading to algal blooms
96. What is the primary pollutant in vehicle exhaust? Carbon monoxide (CO)
97. What is the role of catalytic converters? Reduce harmful emissions
98. What is the main source of water pollution? Industrial effluents
99. What is green chemistry? Designing chemical processes to reduce environmental impact
100. What is the effect of CO₂ increase in the atmosphere? Global warming

NCERT Class 11 Chemistry Important Questions: Conclusion

Preparing with NCERT Class 11 Chemistry important questions empowers students to tackle both school exams and competitive entrances with confidence. By focusing on these carefully curated questions, you can strengthen your understanding of fundamental concepts and improve your problem-solving efficiency. Incorporate these questions into your study routine, practice consistently, and refer to the NCERT textbook for in-depth clarity to excel in Chemistry and lay a solid foundation for Class 12 and beyond.

Also Read: Basic Chemistry Questions and Answers for Class 9 and 10 Students