Test: Chemical Kinetics - 2 - Chemistry MCQ

The fluorescence life time of a molecule in solution is 10 ns. If the fluorescence quantum yield is 0.1, the rate constant of fluorescence decay is

Rate of a reaction; A+B → Products; is given below as a function of different initial concentrations of A and B.

The half life of A in the reaction is :

Sucrose is converted to a mixture of glucose and fructose in a pseudo first order process under alkaline conditions. The reaction has a half˜life of 28.4 min. The time required for the reduction of a 8.0 mM sample of sucrose to 1.0 mM is:

The reaction, 2NO(g) + O₂(g) →2NO₂(g) proceeds via the following steps:

The rate of this reaction is equal to 

1 g of ⁹⁰Sr gas converted to 0.953 g after 2 yr. The half-line of ⁹⁰Sr, and the amount of ⁹⁰Sr remaining after 5 yr are:

How many times will the rate of the elementary reaction 3X + Y → X2Y change if the concentration of the substance X is doubled and that of Y is halved?

A reaction proceeds through the formation of an intermediate B in a unimolecular reaction  :The integrated rate law for this reaction is 

In radical chain polymerization, the quantity given by the rate of monomer depletion, divided by the rate of propagating radical formation is called:

H₂ and Br₂ react to give HBr by the following steps:

The probable rate law for the above sequence is 

The half–line of a order reaction varies with temperature according to:

The half–life time for a reaction at initial concentrations of 0.1 and 0.4 mol^–1 are 200 s and 50 s respectively. The order of the reaction is:

N₂O₂(g) and NO(g) react to form NO₂ according to the stoichiometric equation 

N₂O₂(g) + NO (g) →3NO₂(g) (R1)

At a given temperature and pressure. A possible mechanism for this overall reaction is:

Where NO₃ is an unstable intermediate. What would be the rate expression of the disappearance of N₂O₅ in terms of the concentrations of the stable species and the rate constants given above:

Formation of Z and X is theoretically expected to obey the following kinetic scheme.

An experimentalist wants to verify the above scheme, but can observed and measure the concentration of only X and Z. Is it possible that under certain, the measurements of [X] and [Z] as function of time would lead the experimenter to conclude that the kinetic scheme is as given below, and that the species Y is absent:

Following is the graph between (a – x)^–1 and time t for a second order reaction,

Hence, rate at the start of the reaction is 

Which of the following plots represent(s) the Arrhenius rate equation, k=Ae^–Ea/RT with and

The fraction of group condensed at time t in any stepwise condensation polymerization (overall second order) reaction is 

For the following reaction,

According to Arrhenius equation (K= rate constant and T= Temperature):

The reaction of nitric oxide with ozone takes place according to the following stoichiometry.

The observed rate law for the reaction is found to be

Where α and β are constant. To explain the above rate low, the following reaction scheme has been proposed:

Determine an expression for β .

If the concept of half-life is generalized to quarter–life of a first order chemical reaction, it will e equal to:

The activation energy for the bimolecular reaction A+BC→AB+C is E₀ in the gas phase. If the reaction is carried out in a confined volume of λ³ , the activation energy is expected to:

In a reaction, A+B→Product, rate is doubled when the concentration of B is doubled and the 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: 

The expression for the equilibrium constant (K_eq) for the enzyme catalyzed reaction given below is:

For a reaction involving two steps given below:

Assume that the first step attains equilibrium rapidly. The rate of formation of P is proportional to 

Consider the reaction H₂ + C₂ H₂ → C₂ H₆ the molecular diameters of H₂ and C₂H₄  The pre-exponential factor in the rate constant calculated using collision theory in m³ (mol) ^–1 s^–1 is approximately (For this reaction at 300K,  where the symbols have their usual meanings):

A reaction A → D , involves following mechanism:

The rate law of the reaction may be given as:

A decomposes as 

Concentration of A, is equal to: