The reaction A → B follows first order kinetics. The time taken for 0.8 mole of A to produce 0.6 mole of B is 1 hour. The time taken for conversion of 0.9 mole of A to produce 0.675 mole of B is : 

  • 1 hour

  • 0.5 hour

  • 0.25 hour

  • 2 hour

If the rate of the reaction is equal to the rate constant, the order of the reaction is -

  • 0

  • 1

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  • 3

The temperature dependence of rate constant (k) of a chemical reaction is written in terms of Arrhenius equation,
k = A.e–E*/RT. Activation energy (E*) of the reaction can be calculated by plotting : 

  •  k vs T

  •  k vs 1log T

  •  log k vs 1T

  •  log k vs 1logT

The radioisotope, tritium (H13) has a half-life of 12.3 years. If the initial amount of tritium is 32 mg, how many milligrams of its would remain after 49.2 years :

  • 1 mg

  • 2 mg

  • 4 mg

  • 8 mg

The decomposition of NH3 on platinum surface is a zero order reaction. The rates of production of N2 and H2 if k = 2.5 × 10–4 mol–1 L s–1 will be respectively -

  • 2.5 x 10-4 mol L-1 s-1 and 5.5 x 10-4 mol L-1 s-1

  • 2.5 x 10-4 mol L-1 s-1 and 7.5 x 10-4 mol L-1 s-1

  • 1.5 x 10-4 mol L-1 s-1 and 4.5 x 10-4 mol L-1 s-1

  • 0.5 x 10-4 mol L-1 s-1 and 3.5 x 10-4 mol L-1 s-1

The rate equation of a reaction is expressed as, Rate=K (PCH3OCH3)32

  • (Unit of rate  =  bar min-1)

  • The units of the rate constant will be:

  • 1. bar1/2 min  2. bar2 min-1  3. bar-1 min-2 4. bar-1/2min-1

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The factor(s) that affect the rate of a chemical reaction is/are -

  • Concentration/Pressure of reactants.

  • Temperature

  • Presence of a catalyst 

  • All of the above

The correct statement about the rate constant of a reaction is-

  • Rate constant is nearly doubled with a rise in temperature by 10° 

  • Rate constant becomes half with a rise in temperature by 10° 

  • Rate constant remains unchanged with a rise in temperature by 10° 

  • None of the above

4g

  • The average rate of reaction between the time interval 30 to 60 seconds in the above-mentioned

  • pseudo 1st order reaction is-

  • 1. 6.67 ×10-2 mol L-1 s-12. 2.67 × 10-4 mol L-1 s-1 3. 4.67 × 10-3 mol L-1 s-14. 4.27 × 103 mol L-1 s-1

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A reaction is first order with respect to A and second-order with respect to B. The concentration of B is increased three times. The new rate of the reaction would  : 

  •  Decrease 9 times.

  • Increase 9 times.

  • Increase 6 times.

  • Decrease 6 times.

In a reaction between A and B, the initial rate of reaction (r0) was measured for different initial concentrations of A and B as given below:

4h

The order of the reaction with respect to A and B would be -

  • The order w.r.t A is 0.5 and w.r.t B is zero.

  • The order w.r.t A is 1 and w.r.t B is 0.5

  • The order w.r.t A is 2 and w.r.t B is 1

  • The order w.r.t A is 1.5 and w.r.t B is zero

For a reaction, 2A + B C + D , following observations were recorded:

 4i

The rate law applicable for the above mentioned reaction would be -

  • Rate = k[A]2[B]3

  • Rate = k[A][B]2

  • Rate =  k[A]2[B] 

  • Rate =  k[A][B] 

Given the following observations:

The reaction between A and B is first-order with respect to A and zero-order with respect to B. The value of X and Y are, respectively : 

  •   X = 0.2 mol L-1; Y =  0.08 mol L-1min-1

  •   X = 0.02 mol L-1; Y =  0.08 mol L-1min-1

  •   X = 0.01 mol L-1; Y =  0.8 mol L-1min-1

  •  X = 0.2 mol L-1; Y =  0.8 mol L-1min-1

The rate constant of a radioactive substance is 4 years-1. The value of half-life will be : 

  • 0.05 years

  • 0.17 years

  • 0.26 years-1

  • 1.6 years

During a nuclear explosion, one of the products is 90Sr with a half-life of 28.1 years. If 1µg of 90Sr was absorbed in the bones of a newly born baby instead of calcium, the amount of 90Sr that will remain after 10 years in the now grown up child would be -

  • 0.227 µg 

  • 0.781 µg 

  • 7.81 µg 

  •  2.27 µg 

For the decomposition of azoisopropane to hexane and nitrogen at 543 K, the following data was obtained:

4l

The rate constant of the above reaction would be -

  • 1.21 x 10-3 s-1

  • 2.21 x 10-3 s-1

  • 3.21 x 10-3 s-1

  • 4.21 x 10-3 s-1

For the  reaction 2A + BA2B, rate = kAB2 with k = 2.0×10-6 mol-2L2s-1 and A=0.1 M; B=0.2 M. The initial rate of the reaction will be

 

  • 0.04×10-9 mol L-1 s-1

  • 8×10-8 mol-1L s-1

  •  8×10-9 mol L-1 s-1

  • 8×10-7 mol L-1 s-1

For a first-order reaction, the relationship between time required for 99% completion to the time required for the completion of 90% of the reaction would be

1. t99% = 3 t90%2. t99% = 2 t90%3. t99% = 4 t90%4. t90% = 2t99%

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Given that Rate=kH2O2I-. The dimension of the rate constant in the given rate law is -

  •   molL-1s-1

  •   mol-1Ls-1

  •   mol-1Ls-2

  •   mol-2Ls-1

Consider the following rate expression.

Rate=kCH3CHO32

The order of reaction and dimension of the rate constant are, respectively-

  • 32; k = mol-1Ls-1

  • 3; k = mol-1Ls-1

  • 32;  k = mol12L-12s-1

  • 32; k = mol-12L12s-1

If the concentration of the reactant is made twice, the new rate of reaction for the second order reaction would be-

  • 2 times

  • 4 times

  • 3 times

  •  No change in the rate of the reaction

A first-order reaction takes 40 min for 30% decomposition. Half life of the reaction is-

 

  • 55.9 min

  • 77.9 min

  • 63.9 min

  • 80.9 min

The rate constant for a first-order reaction is 60 s-1. The time required to reduce the initial concentration of the reactant to its 1/16 value is-

  •  5.64×10-2 s

  •  6.64×10-2 s

  •  4.62×10-2 s

  •  0.14×10-2 s

The time required for 10% completion of a first-order reaction at 298K is equal to that required for its 25% completion at 308K. The value of Ea is : 

  •  76.64 J mol-1

  • 66.64 kJ mol-1

  •  76.64 kJ mol-1

  •  70.34 kJ mol-1

The average rate of reaction based on the above graph will be :

1.R2-R1t2-t12. - R2-R1t2-t13. R2t24. -R1-R2t2-t1

 

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Consider the following graph.


The instantaneous rate of reaction at t= 600 sec will be : 

1. - 4.75 ×10-4 mol L-1s-12. 5.75×10-5 mol L-1s-13.  6.75×10-6 mol L-1s-14. -6.75×10-6 mol L-1s-1

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The slope for the given graph is-

  •  1. k2.3032. -k2.3033. -2.303k4. 2.303k

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Consider the following graph:

The nature of the reaction represented in the above-mentioned graph is : 

  • Endothermic reaction

  • Exothermic reaction

  • Both endothermic and exothermic reactions are represented by the same graph.

  • None of the above

The graph between lnK, and 1Tis given below:

The value of activation energy would be -

 1. 207. 8 kJ/mol2. -207. 8 kJ/mol3. 210.8  kJ/mol4. -210.8  kJ/mol

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