JEE Chemistry — MCQ Practice Questions & Answers

Question 1

Which of the following is the correct order of atomic radius?

Accepted Answer

Correct answer: B. Cs > Rb > K > Na — Atomic radius increases down a group in the periodic table. As we go from Na to K to Rb to Cs, the number of shells increases, leading to increased atomic radius.

Answer

A. Na > K > Rb > Cs

Answer

C. K > Na > Cs > Rb

Answer

D. Rb > Cs > Na > K

Question 2

Which of the following elements forms the most stable hydride?

Accepted Answer

Correct answer: B. F — Fluorine forms HF which is the most stable hydride among halogens due to the strong H-F bond (high bond energy ~570 kJ/mol), resulting from fluorine's high electronegativity.

Answer

A. Cl

Answer

C. Br

Answer

D. I

Question 3

Which of the following oxides is amphoteric?

Accepted Answer

Correct answer: B. Al₂O₃ — Al₂O₃ is amphoteric, reacting with both strong acids (forming AlCl₃) and strong bases (forming aluminate ions). Na₂O is basic, SiO₂ is acidic, and P₂O₅ is acidic.

Answer

A. Na₂O

Answer

C. SiO₂

Answer

D. P₂O₅

Question 4

Which of the following has the highest electronegativity value?

Accepted Answer

Correct answer: B. F — Fluorine has the highest electronegativity value (4.0 on Pauling scale) among all elements due to its small size and high nuclear charge.

Answer

A. Cl

Answer

C. O

Answer

D. N

Question 5

Which statement about nitrogen oxides is incorrect?

Accepted Answer

Correct answer: C. N₂O₄ is blue gas — N₂O₄ is colorless gas, not blue. NO is colorless, NO₂ is brown/reddish-brown, and N₂O is indeed called laughing gas.

Answer

A. NO is colorless gas

Answer

B. NO₂ is brown gas

Answer

D. N₂O is laughing gas

Question 6

Which of the following is not a property of noble gases?

Accepted Answer

Correct answer: A. Very low ionization energy — Noble gases have VERY HIGH ionization energies (not low) due to their stable electron configuration. All other options are correct properties of noble gases.

Answer

B. Zero electron affinity (approximately)

Answer

C. Inert chemical behavior

Answer

D. Complete s and p orbital filling

Question 7

The coordination number of Cu²⁺ in CuSO₄·5H₂O is:

Accepted Answer

Correct answer: B. 6 — Cu²⁺ is surrounded by 4 water molecules in the coordination sphere and 2 more from the sulfate ion or additional water molecules, giving octahedral geometry with coordination number 6.

Answer

A. 4

Answer

C. 8

Answer

D. 5

Question 8

Which of the following d-block elements has the configuration [Ar]3d¹⁰4s¹?

Accepted Answer

Correct answer: A. Copper — Copper has atomic number 29 with configuration [Ar]3d¹⁰4s¹. It exhibits anomalous behavior by having a completely filled d-orbital.

Answer

B. Zinc

Answer

C. Nickel

Answer

D. Cobalt

JEE Chemistry - MCQ Practice Questions