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.

HARD

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A catalyst provides a new pathway involving lower amount of activation energy, to make the reaction fast. Which one of the following is/are the result of catalytic action.

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Important Questions on Chemical Kinetics

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

If the first order rate constants for the decomposition of ethyl iodide at

600 K

and

700 K

are

2.0 \times 10^{- 5} s^{- 1}

and

2.0 \times 10^{- 4} s^{- 1}

respectively, the activation energy for this reaction in

{kJmol}^{- 1}

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

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:

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

The highest peak in energy profile diagram for mechanism of alkaline hydrolysis of tertiary butyl bromide represents

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

An exothermic reaction

X \to Y

has an activation energy

30 kJ {mol}^{- 1}

. If energy change

ΔE

during the reaction is

- 20 kJ

, then the activation energy for the reverse reaction in

kJ

is (Integer answer)

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

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>Mechanism of a Chemical Reaction

An endothermic reaction

AB

has an activation energy as

x kJ / mol .

If the energy change of reaction is

y kJ,

the activation energy of the reverse reaction is

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

For a reversible reaction, $A ⇌ B$ , which one of the following statement is wrong from the given energy profile diagram?

Question Image

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

For the reaction

A \to B,

the rate constant

k

(in

s^{- 1}

) is given by

\log_{10} k = 20.35 - \frac{(2.47 \times 10^{3})}{T}

The energy of activation in

kJ {mol}^{- 1}

is ________ . (Nearest integer)
[Given :

R = 8.314 J K^{- 1} {mol}^{- 1}

]

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

An endothermic reaction

A \to B

has an activation energy of

13 kJ {mol}^{- 1}

and the enthalpy change for the reaction is

2 kJ {mol}^{- 1}

. The activation energy of the reaction

B \to A

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

Draw a graph of potential energy vs reaction co-ordinates showing the effect of catalyst on activation energy

(E_{a})

of a reaction.

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

Define activation energy.

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

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>Mechanism of a Chemical Reaction

For a reaction

A \to B,

enthalpy of reaction is

- 4.2 kJ {mol}^{- 1}

and enthalpy of activation is

9.6 kJ {mol}^{- 1} .

The correct potential energy profile for the reaction is shown in the option.

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

The unit of activation energy is

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

According to the following figure, the magnitude of the enthalpy change of the reaction

A + B \to M + N

kJ {mol}^{- 1}

is equal to __________ . (Integer answer)
Question Image

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Mechanism of a Chemical Reaction

A first order reaction is $50 %$ completed in $30$ minutes at $300 K$ and in $10$ minutes at $320 K$ . Calculate the activation energy of the reaction.

( $R = 8.314 J K^{- 1} {mol}^{- 1}$ ).