The World of Metals and Non-metals Part 3: MCQs (Q51–Q75)
📘 Chapter 4 – The World of Metals and Non-metals
🔹 Part 3: Effects of Air and Water (Q51–Q75)
Q51. Which gas in air is mainly responsible for rusting of iron?
A) Nitrogen
B) Oxygen
C) Carbon dioxide
D) Hydrogen
✅ Answer: B) Oxygen
Explanation: Oxygen reacts with iron in the presence of water to form rust.
Q52. Rusting of iron requires:
A) Oxygen only
B) Water only
C) Both oxygen and water
D) Neither
✅ Answer: C) Both oxygen and water
Q53. Which metal does not react with air or water easily?
A) Iron
B) Copper
C) Aluminium
D) Gold
✅ Answer: D) Gold
Explanation: Gold is the least reactive metal and does not corrode in air or water.
Q54. What forms when copper reacts with moist air?
A) Copper oxide
B) Copper carbonate + copper hydroxide (green)
C) Rust
D) Tarnish
✅ Answer: B) Copper carbonate + copper hydroxide (green)
Q55. Aluminium utensils do not corrode easily because:
A) They are not metals
B) They form a protective oxide layer
C) They are non-reactive
D) They absorb water
✅ Answer: B) They form a protective oxide layer
Q56. Which non-metal reacts vigorously with air?
A) Sulphur
B) Phosphorus
C) Carbon
D) Iodine
✅ Answer: B) Phosphorus
Explanation: White phosphorus catches fire in air, so it is kept under water.
Q57. Which gas is necessary for burning of metals?
A) Nitrogen
B) Oxygen
C) Carbon dioxide
D) Helium
✅ Answer: B) Oxygen
Q58. Which metal reacts with cold water to produce hydrogen gas?
A) Iron
B) Copper
C) Sodium
D) Aluminium
✅ Answer: C) Sodium
Q59. Which metal reacts slowly with water and forms rust in air?
A) Copper
B) Iron
C) Gold
D) Silver
✅ Answer: B) Iron
Q60. When aluminium reacts with oxygen, it forms:
A) Aluminium chloride
B) Aluminium oxide
C) Aluminium hydroxide
D) Aluminium sulphate
✅ Answer: B) Aluminium oxide
Q61. Magnesium burns in air to form:
A) Magnesium sulphate
B) Magnesium hydroxide
C) Magnesium oxide
D) Magnesium carbonate
✅ Answer: C) Magnesium oxide
Q62. Which non-metal is essential for respiration?
A) Nitrogen
B) Oxygen
C) Carbon dioxide
D) Sulphur
✅ Answer: B) Oxygen
Q63. Which non-metal is used by plants during photosynthesis?
A) Carbon dioxide
B) Nitrogen
C) Oxygen
D) Hydrogen
✅ Answer: A) Carbon dioxide
Q64. Which of these metals reacts vigorously with steam but not with cold water?
A) Copper
B) Iron
C) Zinc
D) Both B and C
✅ Answer: D) Both B and C
Q65. Which gas is released when metals react with acids?
A) Oxygen
B) Hydrogen
C) Carbon dioxide
D) Nitrogen
✅ Answer: B) Hydrogen
Q66. Sodium and potassium are stored under kerosene because:
A) They dissolve in water
B) They react vigorously with oxygen and water
C) They are light
D) They evaporate
✅ Answer: B) They react vigorously with oxygen and water
Q67. Which of the following metals is least affected by air and water?
A) Iron
B) Copper
C) Silver
D) Gold
✅ Answer: D) Gold
Q68. Which non-metal reacts with hydrogen to form water?
A) Nitrogen
B) Oxygen
C) Sulphur
D) Carbon
✅ Answer: B) Oxygen
Q69. What happens when sulphur is burnt in air?
A) Sulphuric acid is formed
B) Sulphur dioxide gas is formed
C) Sulphur trioxide is formed
D) No reaction
✅ Answer: B) Sulphur dioxide gas is formed
Q70. Iron reacts with moist air to form:
A) Rust
B) Iron chloride
C) Iron sulphide
D) Iron carbonate
✅ Answer: A) Rust
Q71. Which metal does not react with water even at high temperature?
A) Iron
B) Copper
C) Zinc
D) Magnesium
✅ Answer: B) Copper
Q72. Which non-metal reacts with water to form an acid?
A) Sulphur dioxide
B) Oxygen
C) Nitrogen
D) Carbon
✅ Answer: A) Sulphur dioxide
Explanation: SO₂ dissolves in water to form sulphurous acid.
Q73. Which of these metals reacts slowly with cold water but vigorously with steam?
A) Aluminium
B) Iron
C) Zinc
D) Both B and C
✅ Answer: D) Both B and C
Q74. Non-metals generally react with oxygen to form:
A) Metallic oxides
B) Non-metallic oxides (acidic)
C) Neutral substances
D) Bases
✅ Answer: B) Non-metallic oxides (acidic)
Q75. Which of the following is an example of an acidic oxide?
A) Magnesium oxide
B) Sodium oxide
C) Carbon dioxide
D) Calcium oxide
✅ Answer: C) Carbon dioxide
Class 7 Science MCQs, CBSE Science Board Exams, NCERT Science Practice, Metals and Non-metals, Online Learning Science, CBSE Class 7 Science Chapter 4 MCQs, NCERT Class 7 Science metals and non-metals questions, Corrosion Class 7 Science multiple choice questions,
Properties of materials Class 7 Science MCQs, Online learning Class 7 Science exam practice