Consider the given plot of enthalpy of the following reaction between A and B . A + B → C + D . Identify the incorrect statement.

Activation enthalpy to form C is 5 k J m o l - 1 less than that to form D .

Formation of A and B from C has highest enthalpy of activation.

D is kinetically stable product.

C is the thermodynamically stable product.

EASY

Earn 100

Only a few reactions are simple or straight forward, $i . e .$ purely first, second or third order reactions. But in most of the reactions, the interpretation of variety of data becomes difficult due to several other reactions taking place simultaneously along with the main reaction and thus smooth progress of the reaction is disturbed. Such reactions include the following different types. The reactions, in which a substance reacts or decomposes in more than one way, are called parallel or competing or side reaction. The reactions which take place exclusively on the walls of containing vessels are known as surface reactions. The reactions in which the products of chemical change react together to form the original reactants are called reversible reactions or opposing reactions or counter reactions. The reactions which proceeds from reactants to final products through one or more intermediate stages are called consecutive reactions.

The relation $∆ H = E_{a (f)} - E_{a (b)}$ is valid for:

50% studentsanswered this correctly

Important Questions on Chemical Kinetics

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

The rate of a reaction quadruples when the temperature changes from

300

310 K

. The activation energy of this reaction is:

(Assume Activation energy and pre-exponential factor are independent of temperature;

\ln (2) = 0.693; R = 8.314 J {mol}^{- 1} K^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

Two reactions

A_{1}

and

A_{2}

have identical pre-exponential factors. The activation energy of

A_{1}

is more than

A_{2}

10 kJ {mol}^{- 1}

. If

k_{1}

and

k_{2}

are the rate constants for reactions

A_{1}

and

A_{2}

, respectively at

300 K

, then

\ln (\frac{k_{2}}{k_{1}})

is equal to

(R = 8 .314 J {mol}^{- 1} K^{- 1})

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

The rate of a reaction A doubles on increasing the temperature from

300 to 310 K

. By how much, the temperature of reaction B should be increased from

300 K

so that rate doubles if activation energy of the reaction B is twice to that of reaction A.

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

The rate constant of a chemical reaction at a very high temperature will approach

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

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

(I)

Question Image

(II)

Question Image

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

The Arrhenius plots of two reactions, I and II are shown graphically-

Question Image

The graph suggests that-

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

Which among the following equations represents Arrhenius equation?

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

For the following reactions

A \overset{700 K}{\to} Product

A \overset{500 K}{\underset{catalyst}{\to}} Product

It was found that the

E_{a}

is decreased by

30 K J / m o l

in the presence of catalyst. If the rate remains unchanged, the activation energy for catalysed reaction is (Assume pre-exponential factor is same)

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

The addition of a catalyst during a chemical reaction alters which of the following quantities?

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

The enthalpy

(H)

of an elementary exothermic reaction

A ⇌ B

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

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

For the reaction of

H_{2}

with

I_{2}

, the rate constant is

2.5 \times 10^{- 4} d m^{3} m o l^{- 1} s^{- 1}

327^{o} C

and

1.0 d m^{3} m o l - 1 s^{- 1}

527 ° C

. The activation energy for the reaction, in

k J m o l - 1

is:

(R = 8.314 J K^{- 1} m o l^{- 1})

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

For the equilibrium,

A (g) ⇌ B (g), ∆ H is - 40 kJ / mol

. If the ratio of the activation energies of the forward

(E_{f})

and reverse

(E_{b})

reactions is

\frac{2}{3}

then:

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

Consider the given plot of enthalpy of the following reaction between

A

and

B .

A + B \to C + D .

Identify the incorrect statement.
Question Image

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Integrated Rate Law for Zero and First Order Reactions

For a reaction, consider the plot of $l n k$ versus $1 / T$ given in the figure. If the rate constant of this reaction at $400 K$ is $10^{- 5} s^{- 1}$ , then the rate constant at $500 K$ is:

Question Image