🔥🌟 Grand Chemistry MCQs Test for Class 11 | Interactive Quiz 🧪💡 | Learn & Practice!

Welcome to Inamjazbi Learn Chemistry! 🎉 This ultimate Class 11 Chemistry MCQs test covers stoichiometry, atomic structure, chemical bonding, chemical equilibrium, acids, bases and salts,  and much more. Test your knowledge with interactive questions, get instant feedback on each answer, and see your final score at the end! 🧠Keep track of your score and challenge yourself!

Whether you are preparing for exams or just love Chemistry, this quiz is perfect for sharpening your concepts. Ready, set, answer! ⚡

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🔥🌟 Grand Chemistry MCQs Test for Class 11 | Interactive Quiz 🧪💡 | Learn & Practice!

1. The potential energy of an electron can be calculated by

(a) (Ze²)/(8πεₒ r)

(b) - (Ze²)/(4πεₒ r)

(c) (Ze²)/(4πεₒ r)

(d) - (Ze²)/(8πεₒ r)

Correct answer: (b) - This is the formula for potential energy of an electron in a Coulomb field.

2. In the reaction 2Na + 2H₂O → 2NaOH + H₂, if 23g of Na reacts with excess of water, the volume of hydrogen gas (H₂) liberated at STP should be

(a) 11.2dm³

(b) 22.4dm³

(c) 33.6dm³

(d) 44.8dm³

Correct answer: (a) - 11.2dm³ is the volume of hydrogen gas released at STP based on the molar ratio of Na to H₂ in the reaction.

3. Which of the following sample of substances contains the same number of atoms as that of 20g calcium:

(a) 16g S

(b) 20g C

(c) 39g K

(d) 24g Mg

Correct answer: (a) - 16g S contains the same number of atoms as 20g calcium, based on molar masses and Avogadro’s number.

4. Line spectrum is used as a tool for the identification of

(a) Colors

(b) Electrons

(c) Elements

(d) Molecules

Correct answer: (c) - Line spectrum helps identify elements because each element emits unique wavelengths of light when excited.

5. When 4d orbital is filled, the next electron enters into

(a) 5s

(b) 5p

(c) 5d

(d) 6s

Correct answer: (a) - After filling the 4d orbital, the next electron goes into the 5s orbital, according to the Aufbau principle.

6. Which of the following is not an iso electronic pair?

(a) Na⁺ and Ne

(b) Na⁺ and F⁻

(c) Na and Ca

(d) Na⁺ and Mg²⁺

Correct answer: (c) - Na and Ca are not iso electronic because they have different numbers of electrons (Na has 11, Ca has 20).

7. If the bond angle in AB₂ type molecule is 104.5°, its geometry should be:

(a) Linear

(b) Pyramidal

(c) Bent

(d) Planar Trigonal

Correct answer: (c) - A bond angle of 104.5° suggests a bent geometry (e.g., water, H₂O).

8. The highest bond energy in the following is:

(a) Cl–Cl

(b) H–F

(c) H–O

(d) H–N

Correct answer: (b) - H–F has the highest bond energy due to the high electronegativity difference between H and F.

9. The molecule which has zero dipole moment is:

(a) NH₃

(b) HCl

(c) H₂O

(d) CCl₄

Correct answer: (d) - CCl₄ has a symmetrical tetrahedral geometry, leading to zero dipole moment.

10. The molecule which has maximum bond angle:

(a) CS₂

(b) H₂O

(c) NH₃

(d) BF₃

Correct answer: (a) - CS₂ has a linear geometry with 180° bond angles, which is the maximum in this list.

11. The shape and hybridization of BCl₃ molecule is:

(a) Tetrahedral and sp₃

(b) Linear and sp

(c) Planar trigonal and sp₂

(d) Angular and sp₃

Correct answer: (c) - BCl₃ has a trigonal planar shape and sp₂ hybridization due to the central boron atom having three bonding regions.

12. The bond order of N₂ molecule is:

(a) 0

(b) 1

(c) 2

(d) 3

Correct answer: (d) - N₂ has a bond order of 3, calculated from the difference in the number of bonding and antibonding electrons.

13. The number of sigma and pi bonds in C₂H₄ molecules are respectively:

(a) 3 and 1

(b) 2 and 2

(c) 5 and 1

(d) 4 and 2

Correct answer: (c) - C₂H₄ (ethene) has 5 sigma bonds and 1 pi bond due to its double bond between the carbon atoms.

14. The number of bonds in ethyne (C₂H₂) is:

(a) 2 sigma, 2 pi

(b) 3 sigma, two pi

(c) 3 sigma, 3 pi

(d) 2 sigma, 3 pi

Correct answer: (b) - C₂H₂ (ethyne) has 3 sigma bonds and 2 pi bonds, due to the triple bond between the two carbon atoms.

15. The molar volume of oxygen gas is maximum at:

(a) 0°C and 1 atm

(b) 0°C and 2 atm

(c) 25°C and 1 atm

(d) 25°C and 2 atm

Correct answer: (c) - The molar volume of oxygen gas is maximum at 25°C and 1 atm, as per the ideal gas law conditions.

16. The volume of gas would be theoretically zero at:

(a) 0°C

(b) 0 K

(c) 273 K

(d) 273°C

Correct answer: (b) - At 0 K (absolute zero), the volume of an ideal gas would be zero, as molecular motion stops.

17. The shape and hybridization of CH₄ molecule is:

(a) Tetrahedral and sp₃

(b) Linear and sp

(c) Planar trigonal and sp₂

(d) Angular and sp₃

Correct answer: (a) - CH₄ has a tetrahedral shape with sp₃ hybridization, as carbon forms four bonds with hydrogen.

18. The bond order of O₂ molecule is:

(a) 2

(b) 3

(c) 0

(d) 3

Correct answer: (a) - The bond order of O₂ is 2, calculated from the molecular orbital theory.

19. The number of sigma and pi bonds in C₂H₂ molecule are respectively:

(a) 3 and 2

(b) 5 and 2

(c) 5 and 1

(d) 3 and 1

Correct answer: (a) - C₂H₂ (ethyne) has 3 sigma bonds and 2 pi bonds due to its triple bond between the two carbon atoms.

20. If the volume occupied by oxygen gas (O₂) at STP is 11.2 dm³, the number of molecules of O₂ in the vessel are:

(a) 3.01 x 10²³

(b) 6.02 x 10²³

(c) 12.04 x 10²³

(d) 24.08 x 10²³

Correct answer: (a) - At STP, 1 mole of any ideal gas occupies 22.4 dm³, so the number of molecules in 11.2 dm³ is 3.01 x 10²³ (half a mole).

21. The number of carbon atoms in half mole of sugar (C₁₂H₂₂O₁₁) are approximately:

(a) 6 x 10²³

(b) 36 x 10²³

(c) 60 x 10²³

(d) 72 x 10²³

Correct answer: (a) - Half a mole of sugar contains 36 x 10²³ carbon atoms, since 1 mole contains 12 x 10²³ carbon atoms in C₁₂H₂₂O₁₁.

22. If the bond angle in AB₃ type molecule is 107°, its geometry should be:

(a) Linear

(b) Pyramidal

(c) Bent

(d) Planar Trigonal

Correct answer: (c) - A bond angle of 107° suggests a bent geometry (e.g., similar to water). AB₃ with a bond angle around 107° is typically bent.

23. VBT tells us about all of the following facts except:

(a) Bond strength

(b) Bond length

(c) Bond order

(d) Bond energy

Correct answer: (c) - Valence Bond Theory (VBT) does not directly explain bond order; that’s explained by Molecular Orbital Theory (MOT).

24. Conjugate base and conjugate acid of HCO₃⁻ are respectively:

(a) CO₃²⁻ and H₂CO₃

(b) H₂CO₃ and CO₃²⁻

(c) H⁺ and H₂O

(d) CO₃²⁻ and H₂O

Correct answer: (a) - HCO₃⁻ can donate a proton to form CO₃²⁻ (conjugate base) or accept a proton to form H₂CO₃ (conjugate acid).

25. Significant figures in 0.0880 are:

(a) 2

(b) 5

(c) 4

(d) 3

Correct answer: (c) - 0.0880 has 4 significant figures (the trailing zero is significant because it comes after the decimal point).

26. The number of orbitals in the fourth energy level is:

(a) 4

(b) 9

(c) 32

(d) 16

Correct answer: (d) - The fourth energy level (n = 4) contains 16 orbitals: 1 s, 3 p, 5 d, and 7 f orbitals.

27. The geometry of NH₄⁺ and SO₄²⁻ ions is:

(a) Trigonal

(b) Tetrahedral

(c) Pyramidal

(d) Square planar

Correct answer: (b) - Both NH₄⁺ and SO₄²⁻ have tetrahedral geometry, with central atoms surrounded symmetrically by bonds.

28. This pair does not obey Dalton’s law:

(a) He and H₂

(b) HCl and NH₃

(c) H₂ and Ar

(d) He and NH₃

Correct answer: (b) - HCl and NH₃ do not obey Dalton’s law because they react chemically, rather than behaving as ideal gases.

29. The vapor pressure of H₂O at 100°C is:

(a) 76 torr

(b) 101325 pascal

(c) 5 atm

(d) 12.5 psi

Correct answer: (b) - The vapor pressure of water at 100°C is 760 torr or 101325 pascal

30. This oxide is amphoteric:

(a) K₂O

(b) Al₂O₃

(c) CO₂

(d) CaO

Correct answer: (b) - Al₂O₃ is amphoteric, meaning it can react with both acids and bases, unlike the other oxides listed here.

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