Chemical Kinetics

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Question

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Question 1 :

Consider the reaction, 2A + B → Products
When concentration of B alone was doubled, the half-life did not change. When the concentration of A alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is: 

1. no unit
2. mol L^–1s^–1
3. s^–1
4. L mol^–1s^–1
Answer
5171

Question 2 :

Radioactivity of a sample (z = 22) decreases 90% after 10 years. What will be the half-life of the sample?

1. 5 years
2. 2 years
3. 3 years;
4. 10 years
Answer
5172

Question 3 :

The rate of a chemical reaction

1. Increases as the reaction proceeds
2. Decreases as the reaction proceeds
3. May increase or decrease during the reaction
4. Remains constant as the reaction proceeds
Answer
5173

Question 4 :

Read the Assertion and Reason carefully to mark the correct option out of the options given below:

Assertion : According to steady state hypothesis, in a multistep reaction, the change in concentration with time for reactive intermediates is zero.
Reason : The intermediates are so reactive that after a brief initial period their concentrat

1. If both assertion and reason are true and the reason is the correct explanation of the assertion.
2. If both assertion and reason are true but reason is not the correct explanation of the assertion.
3. If assertion is true but reason is false.
4. If the assertion and reason both are false.
5. If assertion is false but reason is true.
Answer
5174

Question 5 :

A first order reaction complete its 10% in 20 minutes then time required to complete its 19% is

1. 30 minutes
2. 40 minutes
3. 50 minutes
4. 38 minutes
Answer
5175