A radioactive isotope having a half-life of 3 days was received a

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 Multiple Choice QuestionsMultiple Choice Questions

551.

For the decomposition reaction of lime stone, the correct expression for rate constant, KP is

  • Kp = pCaO.pCO2pCaCO3

  • Kp = CaOCO2CaCO3

  • Kp = pCaO + pCO2pCaCO3

  • Kp = pCO2


552.

Decomposition of H2O2 is a first order reaction. Initially, solution of H2O2 having half-life time 15 min is 16 volume. When solution becomes 1 volume

  • 4 min

  • 15 min

  • 30 min

  • 60 min


553.

What is the two third life of a first order reaction having k = 5.48 × 10-14s-1?

  • 1 × 1013 s

  • 2 × 1013 s

  • 8 × 1013 s

  • 5 × 1014 s


554.

At room temperature, the reaction between NO and O2 to give NO2 is fast while that of between CO and O2 is slow. It is because

  • the intrinsic energy of the reaction 2NO + O2  2NO2 is less

  • CO is smaller in size than that of NO

  • CO is poisonous

  • the activation energy for the reaction 2 NO + O2  2NO2 is less


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555.

A radioactive isotope having a half-life of 3 days was received after 12 days. It was found that there were 3 g of the isotope in the container. Find the initial weight of the isotope, when it was packed (antilog 1.203 = 16)

  • 12 gm

  • 24 gm

  • 36 gm

  • 48 gm


D.

48 gm

No. of half-lives, n = 123 = 4

Amount left after n half-lives = A02n

3 gm = A0243 gm = A016    A0 = 48 gm


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556.

Transition state 2 (TS2) is structurally most likely as a/an

  

  • intermediate 2

  • product

  • intermediate 1

  • transition state 3(TS3)


557.

Which graph shows zero activation energy for reaction?


558.

Which of the following is correct for a first order reaction?

  • t1/2 ∝ a°

  • t1/2  ∝ a2

  • t1/2  ∝ a

  • t1/2  ∝ 1/a


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559.

During nuclear explosion one of the products is 90Sr with half-life of 28.1 yr. If 1 μg of 90Sr was absorbed in the bones of a newly born body instead of calcium, how much of it will remain after 60 yr, if it is not lost metabolically?

  • 0.184 μg

  • 0.025 μg

  • 0.262 μg

  • 0.228 μg


560.

The half-life period of a radioactive element is 30 days. After 90 days, which of the following quantity will be left?

  • 1/2

  • 1/6

  • 1/8

  • 1/4


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