For a reaction A → B, the Arrhenius equation is given as \(log_{e}k \ = \ 4 \ - \ \frac{1000}{T}\) the activation energy in J/mol for the given reaction will be:
1. 8314
2. 2000
3. 2814
4. 3412
The half-life of the two samples is 0.1 and 0.4 seconds, respectively. Their concentrations are 200 and 50, respectively. The order of the reactions will be:
1. 0
2. 2
3. 1
4. 4
For a first-order reaction , rate constant (k) [dependent on temperature (T)] was found
to follow the equation \(log \ k \ = \ (-2000)\frac{1}{T} \ + \ 6.0\). The pre-exponential factor A and
the activation energy , respectively, are:
1.
2.
3.
4.
The half-life of 92U238 against \(\alpha\)-decay is 4.5 × 109 year. The time taken in a year for the decay of the 15/16 part of this isotope will be:
1.
2.
3.
4.
For a chemical reaction product, the postulated mechanism of the reaction is as follows.
\(E_{a_{1}} = 180 \ kJ \ mol^{-1}, \)
\( E_{a_{2}} = 90 \ kJ \ mol^{-1}, \)
\( E_{a_{3}} = 40 \ kJ \ mol^{-1}\)
then overall activation energy for the reaction given above is
1. 70 kJ mol-1
2. -10 kJ mol-1
3. 310 kJ mol-1
4. 130 kJ mol-1
Select the correct option based on statements below:
Assertion (A): | The overall order of reaction is the sum of the power of all the reactants in the rate expression. |
Reason (R): | There are many higher-order reactions. |
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. |
Select the correct option based on statements below:
Assertion (A): | Base catalyzed hydrolysis of ethyl acetate is a first-order reversible reaction. |
Reason (R): | The order of reaction always depends on the stoichiometry of the reaction. |
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. |
Select the correct option based on statements below:
Assertion (A): | At very high temperatures (approaches to infinity), the rate constant becomes equal to the collision frequency. |
Reason (R): | The collision in which molecules collide with proper orientation is called an ineffective collision. |
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. |
Select the correct option based on statements below:
Assertion (A): | For elementary reactions, the law of mass action and the rate of law expression are generally the same. |
Reason (R): | The molecularity of an elementary reaction is always one. |
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. |
If a reaction A + B → C is exothermic to the extent of 30 kJ mol−1 and the forward reaction has an activation energy of 249 kJ mol−1, the activation energy for the reverse reaction in kJ mol-1 will be:
1. | 324 | 2. | 279 |
3. | 40 | 4. | 100 |