Chemical Kinetics

A reaction is 50\% complete in 2 hours and 75\% complete in 4 hours. The order of reaction is

1. 1
2. 2
3. 3
4. 0

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 )

In a reaction, A + B product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate law for the reaction can be written as

1. rate = k[A][B]2
2. rate = k[A]2[B]2
3. rate = k[A][B]
4. rate = k[A]2[B]

In a zero-order reaction, for every 10 rise of temperature, the rate is doubled. If the temperature is increased from 10 to 100 , the rate of the reaction will become

1. 256 times
2. 512 times
3. 64 times
4. 128 times

The rate of the reaction: 2N2O5 4NO2 + O2 can be written in three ways. -d[N2O5]dt = k [N2O5] d[NO2]dt = k' [N2O5]; d[O2]dt = k'' [N2O5] The relationship between k and k' and between k and k'' are

1. k' = 2k; k'' = k
2. k' = 2k; k'' = k/2
3. k' = 2k; k'' = 2k
4. k' = k; k'' = k

The unit of rate constant for a zero order reaction is

1. mol L-1 s-1
2. L mol-1 s-1
3. L2 mol-2 s-1
4. s-1

The half-life of a substance in a certain enzyme-catalysed reaction is 138 s. The time required for the concentration of the substance to fall from 1.28 mg L-1 to 0.04 mg L-1 is

1. 414 s
2. 552 s
3. 690 s
4. 276 s

Which one of the following statements for the order of a reaction is incorrect?

1. Order can be determined only experimentally.
2. Order is not influenced by stoichiometric coefficient of the reactants.
3. Order of a reaction is sum of power to the concentration terms of reactants to express the rate of reaction.
4. Order of reaction is always whole number.

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.

For an endothermic reaction, energy of activation is Ea and enthalpy of reaction is H (both of these in kJ/mol). Minimum value of Ea will be

1. less than H
2. equal to H
3. more than H
4. equal to zero