Consider the following nuclear reactionsThe number of neutrons i

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 Multiple Choice QuestionsMultiple Choice Questions

31.

The rate equation for the reaction 2A + B → C is found to be: rate k[A][B]. The correct statement in relation to this reaction is that the

  • unit of K must be s-1

  • values of k is independent of the initial concentration of A and B

  • rate of formation of C is twice the rate of disappearance of A

  • rate of formation of C is twice the rate of disappearance of A

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32.

The soldiers of Napolean army while at Alps during freezing winter suffered a serious problem as regards to the tin buttons of their uniforms. White metallic tin buttons got converted to grey powder. This transformation is related to

  • an interaction with nitrogen of the air at very low temperatures

  • an interaction with water vapour contained in the humid air

  • a change in the partial pressure of oxygen in the air

  • a change in the partial pressure of oxygen in the air

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33.

Consider the following nuclear reactions

straight M presubscript 92 presuperscript 238 space rightwards arrow with space on top space straight N presubscript straight y presuperscript straight x space plus space He presubscript 2 presuperscript 4
straight N presubscript straight y presuperscript straight x space rightwards arrow with space space on top space straight L presubscript straight B presuperscript straight A space plus space 2 straight beta to the power of plus mai
The number of neutrons in the element L is

  • 142

  • 164

  • 144

  • 144


C.

144

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34.

The half-life of a radioisotope is four hours. If the initial mass of the isotope was 200 g, the mass remaining after 24 hours undecayed is

  • 1.042 g

  • 4.167 g

  • 3.125 g

  • 3.125 g

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35.

The compound formed in the positive test for nitrogen with the Lassaigne solution of an organic compound is

  • Fe4[Fe(CN)6]3

  • Na4[Fe(CN)5NOS]

  • Fe(CN)3

  • Fe(CN)3

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36.

At 5180C the rate of decomposition of a sample of gaseous acetaldehyde initially at a pressure of 363 Torr, was 1.00 Torr s–1 when 5% had reacted and 0.5 Torr s–1 when 33% had reacted. The order of the reaction is

  • 0

  • 2

  • 3

  • 1


37.

An aqueous solution contains 0.10 M H2S and 0.20 M HCl. If the equilibrium constants for the formation of HS– from H2S is 1.0 x10–7 and that of S2- from HS ions is 1.2 x 10–13 then the concentration of S2- ions in aqueous solution is

  • 5 x 10-19

  • 5 x 10-8

  • 3 x 10–20

  • 6 x 10-21


38.

For the reaction A +2B → C, the reaction rate is doubled, if the concentration of A is doubled. The rate is increased by four times when concentrations of both A and B are increased by four times. The order of the reaction is

  • 3

  • 0

  • 1

  • 2


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39.

The increase in rate constant of a chemical reaction with increasing temperature is (are) due to the fact(s) that

  • the number of collisions among the reactant molecules increases with increasing temperature

  • the activation energy of the reaction decreases with increasing temperature

  • the concentration of the reactant molecules increases with increasing temperature

  • the number of reactant molecules acquiring the activation energy increases with increasing temperature


40.

The rate of a certain reaction is given by, rate = k [H+]n. The rate increases 100 times when the pH changes from 3 to 1. The order (n) of the reaction is

  • 2

  • 0

  • 1

  • 1.5


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