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 Multiple Choice QuestionsMultiple Choice Questions

51.

The concentrations of the reactant A in the reaction A → B at different times are given below

Concentration (M) Time (minutes)
0.069 0
0.052 17
0.035 34
0.018  51

The rate constant of the reaction according to the correct order of the reaction is

  • 0.001 M/min

  • 0.001 min-1

  • 0.001 min/M

  • 0.001 M-1 min-1


52.

The half-life of two samples are 0.1 and 0.8 s. Their respective concentration are 400 and 50 respectively. The order of the reaction is

  • 0

  • 2

  • 1

  • 4


53.

Acid hydrolysis of ester is first order reaction and rate constant is given by

k = 2.303t log V - V0V - Vt

where, V0, Vt and V∞ are the volume of standard NaOH required to neutralise acid present at a given time, if ester is 50% neutralised then

  • V = Vt

  • V∞ = (Vt - V0)

  • V = 2Vt - V0

  • V∞ = 2Vt + V0


54.

Consider the following reaction,

The reaction is of first order in each diagram, with an equilibrium constant of 104. For the conversion of chair form to boat form e-Ea/RT = 4.5 × 10-8 m at 298 K with pre-exponential factor of 1012 s-1. Apparent rate constant (=kA/ kB) at 298 K is

  • 4.35 × 104 s-1

  • 4.35 × 10s-1

  • 4.35 × 10-8 s-1

  • 4.35 × 1012s-1


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55.

The unit of rate constant for a zero order reaction is

  • mol L-1 s-1

  • L mol-1 s-1

  • L2 mol-2s-1

  • s-1


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56.

In the reversible reaction,

2NO2 k2k1 N2O4

the rate of disapperance of NO2 is equal to

  • 2k1k2[NO2]2

  • 2k1[NO2]2 - 2k2[N2O4]

  • 2k1[NO2]2 - k2[N2O4]

  • (2k1-k2)[NO2]


B.

2k1[NO2]2 - 2k2[N2O4]

2NO2k2k1 N2O4Rate= -12d[NO2]dt=k1[NO2]2- k2[N2O4]

Rate of disappearance of NO2 i.e, -d[NO2]dt= 2k1[NO2]2-2k1[N2O4]


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57.

A chemical reaction was carried out at 300 K and 280 K. The rate constants were found to be k1 and k2 respectively. Then

  • k2= 4k1

  • k2=2k1

  • k2=0.25k1

  • k2=0.5k1


58.

The rate constant of a reaction at temperature 200 K is 10 times less than the rate constant at 400 K. What is the activation energy of the reaction?

  • 1842.4 R

  • 460.6 R

  • 230.3 R

  • 921.2 R


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59.

For a reaction of type A + B products, it is observed that doubling concentration of A causes the reaction rate to be four times as great, but doubling amount of B does not affect the rate. The unit of rate constant is

  • s-1

  • s-1 mol L-1

  • s-1 mol-1 L

  • s s-1 mol-2 L-2


60.

A chemical reaction was carried out at 320 K and 300 K. The rate constants were found to be k1 and k2 respectively. Then

  • k2= 4k1

  • k2 = 2k1

  • k2= 0.25 k1

  • k2=  0.5k1


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