Chemical Kinetics

Given below is an expression for the rate constant of a first-order reaction occurring at a certain temperature, T (K). ln k = 14.34 − 1.25 104T The energy of activation in kcal mol-1 for the reaction is : (Given : k in s-1, R = 1.987 cal mol-1 K-1)

1. 12.42
2. 18.63
3. 14.34
4. 24.84

For an elementary chemical reaction, the Arrhenius plot is given below. [figure] If the energy of activation is 6.64 kJ mol-1 and R = 8.3 J K-1 mol-1, the temperature at which the rate constant becomes e2 min-1, is

1. 250 K
2. 125 K
3. 150 K
4. 200 K

Activation energy of any chemical reaction can be calculated if one knows the value of

1. rate constant at standard temperature
2. probability of collision
3. orientation of reactant molecules during collision
4. rate constant at two different temperatures

Which plot of k vs 1T is consistent with Arrhenius equation?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

The rate of a reaction quadruples when temperature changes from 27 to 57 . Calculate the energy of activation. Given R = 8.314 J K-1 mol-1, 4 = 0.6021

1. 38.04 kJ/mol
2. 380.4 kJ/mol
3. 3.80 kJ/mol
4. 3804 kJ/mol

Which of the following plot represents the variation of k versus 1T in accordance with Arrhenius equation?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Rate constants of a reaction at 500 K and 700 K are 0.04 s-1 and 0.14 s-1, respectively; then, activation energy of the reaction is : (Given: 3.5 = 0.5441, R = 8.31 J K-1 mol-1)

1. 182310 J
2. 18500 J
3. 18219 J
4. 18030 J

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. In the light of the above statements, choose the correct answer from the options given below:

1. Both A and R are true but R is NOT the correct explanation of A.
2. A is true but R is false.
3. A is false but R is true.
4. Both A and R are true and R is the correct explanation of A.

The slope of Arrhenius plot ( ln k v/s 1T ) of first order reaction is -5 103 K. The value of Ea of the reaction is. Choose the correct option for your answer. [Given R = 8.314 J K-1 mol-1]

1. -83 kJ mol-1
2. 41.5 kJ mol-1
3. 83.0 kJ mol-1
4. 166 kJ mol-1

The activation energy of a reaction can be determined from the slope of which of the following graphs?

1. k vs. 1T
2. T k vs. 1T
3. k vs. T
4. kT vs. T

What is the activation energy for a reaction if its rate doubles when the temperature is raised from 20 C to 35 C? (R = 8.314 J mol-1 K-1)

1. 34.7 kJ mol-1
2. 15.1 kJ mol-1
3. 342 kJ mol-1
4. 269 kJ mol-1

Activation energy (Ea) and rate constants (k1 and k2) of a chemical reaction at two different temperatures (T1 and T2) are related by

1. k2k1 = - EaR ( 1T1 - 1T2 )
2. k2k1 = - EaR ( 1T2 - 1T1 )
3. k2k1 = - EaR ( 1T2 + 1T1 )
4. k2k1 = EaR ( 1T1 - 1T2 )

The rate of the reaction, 2NO + Cl2 2NOCl is given by the rate equation rate = k[NO]2[Cl2]. The value of the rate constant can be increased by

1. increasing the temperature
2. increasing the concentration of NO
3. increasing the concentration of the Cl2
4. doing all of these.

The rate constants k1 and k2 for two different reactions are 1016 e-2000/T and 1015 e-1000/T, respectively. The temperature at which k1 = k2 is

1. 2000 K
2. 10002.303 K
3. 1000 K
4. 20002.303 K

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

1. k vs T
2. k vs 1 T
3. log k vs 1T
4. log k vs 1 T