Question 71 : Powdered marble reacts more rapidly with HCL than the chips of marble because:
1. Energy of activation decreases
2. None of these
3. Number of molecules increases.
4. Surface area of powdered marble is more that of chips of marble and hence there is more collisions between the molecules of reactants
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Question 72 : Rusting of iron Is an example of________ reaction
1. none of these
2. slow
3. Moderate
4. Fast
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Question 73 : 2N0₂ + 0₂ ——> P₂ NO₂ The above reaction is:
1. Bimolecular
2. Unimolecular
3. Trimolecular
4. None of these
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Question 74 : The reactions catalyzed by sunlight are called reactions
1. Exothermic
2. None of these
3. Photochemical
4. Endothermic
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Question 75 : in a reaction: 2A→B + 2C, which of the statement is true?
1. Rate of formation of B = Rate of disappearance of A
2. Rate of disappearance of A=Rate of formation of C
3. Rate of formation of C= Rate of formation of B
4. None of these
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Question 76 : Which of the following are best to explain the action of negative catalyst in a chemical reaction?
1. It decreases the rate of reaction because rate constant for the reaction increases.
2. It decreases the rate of the reaction because smaller fraction of the total molecules will react due to increase of energy activation.
3. None of These
4. It decreases the rate constant because the adding catalyst recovered unchanged at the end of the reaction
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Question 77 : The reactions with the high value of energy of activation are?
1. Moderate
2. Fast
3. Slow
4. None of these
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Question 78 : In the reaction: 2B→ Product If the concentration of 'B' is doubled, the rate of reaction will increase by?
1. Four times
2. Three times
3. None of these
4. Two times
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