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Question #1

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Which of the following is a negative catalyst (inhibitor)?

A. Pt in oxidation of SO₂

B. Fe in Haber process

C. Phosphoric acid in decomposition of H₂O₂

D. MnO₂ in decomposition of H₂O₂

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Correct Answer: Option C

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Explanation:
A negative catalyst (inhibitor) slows down a reaction. Phosphoric acid (or acetamide) retards the decomposition of H₂O₂ by stabilizing it. MnO₂ is a positive catalyst for H₂O₂ decomposition, speeding it up. Platinum catalyzes SO₂ oxidation in contact process. Iron (Fe) catalyzes ammonia synthesis in Haber process. Negative catalysts are often used to prevent undesirable reactions, e.g., antioxidants in food preservation.

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This question belongs to: Science chemistry

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Question #2

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Assertion (A): Hydrogen is a better fuel than CNG. Reason (R): Hydrogen is highly explosive and difficult to store safely.

A. A is true but R is false.

B. Both A and R are true but R is NOT the correct explanation of A.

C. Both A and R are true and R is the correct explanation of A.

D. A is false but R is true.

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Correct Answer: Option B

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Explanation:
Hydrogen has a higher calorific value than CNG, making it a better fuel in terms of energy output per unit mass. However, R states it is explosive and hard to store, which is a disadvantage, not the reason it is a better fuel. Thus, both are true, but R does not explain A.

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This question belongs to: Science chemistry

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Question #3

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Petroleum refining involves:

A. Fractional distillation

B. Crystallization

C. Electrolysis

D. Sublimation

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Correct Answer: Option A

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Explanation:
Crude oil is separated into fractions (petrol, kerosene, diesel, etc.) based on boiling points by fractional distillation. Cracking, reforming are secondary processes.

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