MEDIUM
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If a is the initial concentration of the reactant, the half-life period of the reaction of nth order is proportional to which of the following?

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Important Questions on Chemical Kinetics

HARD
Consider the following reversible reaction:

A g+B gAB g

The activation energy of the backward reaction exceeds that of the forward reaction by 2RT (in  mol-1). If the pre-exponential factor of the forward reaction is 4 times that of the reverse reaction, the absolute value of G  (in J mol-1) for the reaction at 300 K is ____.

(Given; ln2= 0.7,  = 2500 J mol-1 at 300 K and G is the Gibbs energy)
HARD

For an elementary chemical reaction, A2 k-1k12A , the expression for dAdt is:

HARD
For a first order reaction A(g)  2B(g) + C(g) at constant volume and 300 K, the total pressure at the beginning (t = 0) and at time are  p0 and pt, respectively. Initially, only A is present with concentration  A0, and  t13  is the time required for the partial pressure of A to reach 1/3rd of its initial value. The correct option(s) is (are)
(Assume that all these gases behave as ideal gases)
HARD
The reaction 2N2O5g4NO2g+O2(g) follows first order kinetics. The pressure of a vessel containing only N2O5 was found to increase from 50 mm Hg to 87.5 mm Hg in 30 min. The pressure exerted by the gases after 60 min. Will be (Assume temperature remains constant) :
MEDIUM
The rate of a first-order reaction is 0.04 mol l-1s-1 at 10 second and 0.03 mol l-1s-1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is:
EASY
The rate of a reaction doubles when its temperature changes from 300K to 310K. Activation energy of such a reaction will be:

R=8.314 JK-1mol-1 and log 2=0.301
MEDIUM

For a reaction, consider the plot of lnk versus 1/T given in the figure. If the rate constant of this reaction at 400K is 10-5s-1 , then the rate constant at 500K is:

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MEDIUM
A reaction has an activation energy of 209 kJ mol-1 . The rate increases 10 -fold when the temperature is increased from 27oC to XoC . The temperature X is closest to

[Gas constant, R=8.314 J mol-1K-1 ]
HARD

Consider the given plots for a reaction obeying Arrhenius equation (0°C<T<300°C): ( K and Ea are rate constant and activation energy, respectively )

(I) 

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(II) 

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EASY
Decomposition of X exhibits a rate constant of 0.05μg/year. How many years are required for the decomposition of 5μg of X into 2.5μg?
EASY
A+2BC , the rate equation for the reaction is given as

Rate =k[A][B]

If the concentration of A is kept the same but that of B is doubled what will happen to the rate itself?
EASY
For the equilibrium, AgBg, H is -40 kJ/mol . If the ratio of the activation energies of the forward Ef and reverse Eb reactions is 23 then:
EASY
The rate constant of the reaction AB is 0.6×10-3 mole per liter per second. If the initial concentration of A is 5 M, then the concentration of B after 20 minutes is:
MEDIUM
For the non-stoichiometry reaction,  2 A + B C + D , the following kinetic data were obtained in three separate experiments, all at 298 K.
Initial Concentration (A) Initial Concentration (B) Initial rate of formation of C mol L - S -  
0.1 M 0.1 M 1.2 × 1 0 - 3
0.1 M 0.2 M 1.2 × 1 0 - 3
0.2 M 0.1 M 2.4 × 1 0 - 3

The rate law for the formation of C is 
EASY
When initial concentration of a reactant is doubled in a reaction, its half-life period is not affected. The order of the reaction is:
EASY
The enthalpy (H) of an elementary exothermic reaction AB is schematically plotted against the reaction coordinate. The plots in the presence and absence of a catalyst are shown in dashed and solid lines, respectively. Identify the correct plot for the reaction.
MEDIUM
For the reaction, 2A+B products, when the concentration of A and B both were doubled, the rate of the reaction increased from 0.3 mol L-1s-1 to 2.4 mol L-1s-1.  When the concentration of A alone is doubled, the rate increased from 0.3 mol L-1s-1 to 0.6 mol L-1s-1.

Which one of the following statements is correct?
EASY
The addition of a catalyst during a chemical reaction alters which of the following quantities?
EASY
For nth  order of reaction, Half-life period is directly proportional to