Q. No.
Rate law for the reaction \(A+2 B \rightarrow C\) is found to be
Rate = k[A][B]
If the concentration of reactant 'B' is doubled, keeping the concentration of A constant, then the value of the rate of the reaction will be:
| 1. | The same. | 2. | Doubled. |
| 3. | Quadrupled. | 4. | Halved. |
An incorrect statement about the collision theory of chemical reaction is:
| 1. | It considers reacting molecules or atoms to be hard spheres and ignores their structural features. |
| 2. | The number of effective collisions determines the rate of reaction. |
| 3. | The collision of atoms or molecules possessing sufficient threshold energy results in product formation. |
| 4. | Molecules should collide in the proper orientation for the collision to be effective with sufficient threshold energy and proper orientation. |
A first-order reaction is 50 % completed in 1.26 × 1014 s. The time required for 100 % completion of the reaction will be:
1. 1.26 × 1015 s
2. 2.52 × 1014 s
3. 2.52 × 1028 s
4. Infinite
Compounds A and B react according to the following chemical equation.
A(g) + 2B(g) 2C(g)
The concentration of either A or B was changed keeping the concentrations of one of the reactants constant and rates were measured as a function of initial concentration. The following results were obtained. Choose the correct option for the rate equations for this reaction.
| Experiment | Initial concentration of [A]/mol L–1 |
Initial concentration of [B]/moI L–1 |
Initial rate (mol L–1 s–1) |
| 1. 2. 3. |
0.30 0.30 0.60 |
0.30 0.60 0.30 |
0.10 0.40 0.20 |
2.
3.
4.
An incorrect statement regarding a catalyst is:
| 1. | It catalyzes the forward and backward reactions to the same extent. |
| 2. | It alters the 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. |
The value of the rate constant of a pseudo-first-order reaction:
| 1. | Depends on the concentration of reactants present in a small amount. |
| 2. | Depends on the concentration of reactants present in excess. |
| 3. | Is independent of the concentration of reactants. |
| 4. | Depends only on temperature. |
Consider the reaction AB. The concentration of both the reactant and the product varies exponentially with time.
The graph that accurately depicts how reactant and product concentrations change with time is:
| 1. |  |
2. |  |
| 3. |  |
4. |  |
Rate law expression cannot be determined from a balanced chemical equation if.
| (a) | The reverse reaction is involved. |
| (b) | It is an elementary reaction. |
| (c) | It is a sequence of elementary reactions. |
| (d) | Any of the reactants is in excess. |
The correct choice among the given is:
1. (a, b and c)
2. (b, c and d)
3. (a, c and d)
4. (a, b and d)
The correct statements among the following regarding a balanced chemical equation of an elementary reaction are-
| a. | Order is the same as molecularity. |
| b. | Order is less than the molecularity. |
| c. | Order is greater than molecularity. |
| d. | Molecularity can never be zero. |
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)
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