Q71. Which of the following statements is not true about hydrogen?
A) It has the highest calorific value of all known fuels.
B) It is a colorless and odorless gas.
C) It is highly soluble in water.
D) It is highly inflammable.
Answer: C) It is highly soluble in water.
Explanation: Hydrogen is only sparingly soluble in water, not highly soluble.
Q72. Which of the following is not a method of producing hydrogen gas?
A) Reaction of metals with acids
B) Electrolysis of water
C) Combustion of hydrocarbons
D) Reaction of metals with bases
Answer: C) Combustion of hydrocarbons
Explanation: The combustion of hydrocarbons produces carbon dioxide and water, not hydrogen gas.
Q73. Which of the following reactions does not involve the production of hydrogen gas?
A) Zn + H₂SO₄ → ZnSO₄ + H₂
B) Mg + HCl → MgCl₂ + H₂
C) Fe + H₂O → Fe₃O₄ + H₂
D) Cu + HCl → CuCl₂ + H₂
Answer: D) Cu + HCl → CuCl₂ + H₂
Explanation: Copper does not react with HCl to produce hydrogen because it is less reactive than hydrogen.
Q74. What is the major industrial use of hydrogen?
A) Production of water
B) Production of hydrocarbons
C) Production of ammonia
D) Production of hydrogen peroxide
Answer: C) Production of ammonia
Explanation: Hydrogen is mainly used industrially in the Haber process for the production of ammonia.
Q75. Which of the following is a feature of atomic hydrogen?
A) It is highly stable.
B) It exists only at very high temperatures.
C) It is used in the synthesis of D₂O.
D) It forms diatomic hydrogen immediately.
Answer: B) It exists only at very high temperatures.
Explanation: Atomic hydrogen is highly reactive and exists only at high temperatures before recombining into diatomic hydrogen.
Q76. When hydrogen gas is passed over heated copper oxide, it forms:
A) Copper and water
B) Copper and oxygen
C) Copper oxide and hydrogen peroxide
D) Copper chloride and water
Answer: A) Copper and water
Explanation: Hydrogen reduces copper oxide (CuO) to copper, forming water as a byproduct.
Q77. The oxidation state of hydrogen in metal hydrides such as NaH is:
A) +1
B) 0
C) -1
D) +2
Answer: C) -1
Explanation: In metal hydrides, hydrogen has an oxidation state of -1 as it gains an electron from the metal.
Q78. Which of the following statements is correct about hydrogen bonding in water?
A) It makes water less dense than ice.
B) It makes water molecules less associated.
C) It results in a high boiling point for water.
D) It makes water an ionic compound.
Answer: C) It results in a high boiling point for water.
Explanation: Hydrogen bonding leads to strong intermolecular forces in water, causing it to have a high boiling point compared to other similar-sized molecules.
Q79. Hydrogen combines with oxygen to form water, releasing a large amount of energy. This reaction is called:
A) Oxidation
B) Reduction
C) Combustion
D) Hydrogenation
Answer: C) Combustion
Explanation: When hydrogen combines with oxygen to form water, the process is a combustion reaction, releasing a large amount of energy.
Q80. The catalyst used in the preparation of hydrogen by the reaction of water gas with steam is:
A) Iron
B) Nickel
C) Platinum
D) Vanadium
Answer: B) Nickel
Explanation: Nickel is used as a catalyst in the water-gas shift reaction to increase hydrogen production.
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