The role of a catalyst is to change:
1. | Gibbs energy of the reaction |
2. | Enthalpy of reaction |
3. | The activation energy of the reaction |
4. | Equilibrium constant |
The correct statements among the following is:
(a) | Catalyst provides an alternative pathway to the reaction mechanism |
(b) | Catalyst raises the activation energy |
(c) | A catalyst lowers the activation energy |
(d) | Catalyst alters enthalpy change of the reaction |
1. | (a, b) | 2. | (b, c) |
3. | (c, d) | 4. | (a, c) |
An incorrect statement regarding the catalyst is:
1. | It catalyzes the forward and backward reactions to the same extent. |
2. | It alters gibbs free energy of the reaction. |
3. | It is a substance that does not change the equilibrium constant of a reaction. |
4. | It provides an alternate mechanism by reducing activation energy between reactants and products. |
Select the correct option based on statements below:
Assertion (A): | The enthalpy of reaction remains constant in the presence of a catalyst. |
Reason (R): | A catalyst participating in the reaction forms a different activated complex and lowers down the activation energy but the difference in energy of the reactant and the product remains the same. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
In the presence of a catalyst, the heat evolved or absorbed during the reaction:
1. | Increases. | 2. | Decreases. |
3. | Remains unchanged. | 4. | May increase or decrease. |
Column I (Thermodynamic/Kinetic Principle) |
Column II (Impact on Reaction Dynamics) |
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A. | Catalyst alters the rate of reaction | 1. | Proper orientation is not there always |
B. | 2. | By lowering the activation energy | |
C. | Energetically favorable reactions are sometimes slow | 3. | Total probability is one |
D. | The area under the Maxwell-Boltzmann curve is constant | 4. | Refers to the fraction of molecules with energy equal to or greater than the activation energy |
Codes:
A | B | C | D | |
1. | 2 | 4 | 1 | 3 |
2. | 3 | 1 | 4 | 2 |
3. | 1 | 4 | 3 | 2 |
4. | 3 | 4 | 1 | 2 |
The factor(s) that affect the rate of a chemical reaction is/are:
1. | Concentration/Pressure of reactants. |
2. | Temperature. |
3. | Presence of a catalyst. |
4. | All of the above. |