For the reaction system,2NO (g) + O2 (g) → 2NO2 (g)volume is

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 Multiple Choice QuestionsMultiple Choice Questions

241.

The rate law for a reaction between the substances A and B is given by rate = k[A]n[B]m. On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as 

  • 12m + n

  • (m + n)

  • (n - m)

  • 2(n - m)


242.

What is the half-life of 6C14, if its disintegration constant is 2.31× 10-4 year-1?

  • 0.3 × 10year

  • 0.3 × 10year

  • 0.3 × 10year

  • 0.3 × 10year


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243.

For the reaction system,

2NO (g) + O2 (g) → 2NO2 (g)

volume is suddenly reduced to half its value by increasing the pressure on it. If the reaction is of first order with respect to O2 and second order with respect to NO; the rate of reaction will

  • diminish to one-fourth of its initial value

  • diminish to one-eighth of its initial value

  • increase to eight times of its initial value

  • increase to four times of its initial value


C.

increase to eight times of its initial value

dxdt = k[NO]2[O2]         = knNOV2nO2Vdxdt = kV3 (nNO)2(nO2)         = k(nNO)2(nO2)V23         = 8dxdt

Therefore, the rate of reaction will increase to eight times of its initial value.


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244.

The radioisotope, tritium (13H) has a half-life of 12.3 yr. If the initial amount of tritium is 32 mg, how many milligrams of it would remain after 49.2 yr ?

  • 4 mg

  • 8 mg

  • 1 mg

  • 2 mg


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245.

The activity of a radioactive substance falls to 87.5% of the initial value in 5 years. What is the half-life of the element ?

  • 52 years

  • 104 years

  • 26 years

  • 13 years


246.

A reaction proceeds by first order, 75% of this reaction was completed in 32 min. The time required for 50% completion is

  • 8 min

  • 16 min

  • 20 min

  • 24 min


247.

Time period of a wave is 5 × 10-3 s, what is the frequency?

  • 5 × 10-3 s-1

  • 2 × 10s-1

  • 2.3 × 10s-1

  • 5 × 10s-1


248.

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


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249.

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


250.

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


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