Q. No.A hydrogenation reaction is carried out at 500 K. When the same reaction is carried out in the presence of a catalyst, it proceeds at the same rate with the same frequency factor at 400 K.
The catalyst lowers the activation energy by 16 kJ mol⁻¹.
What is the activation energy of the uncatalyzed reaction (in kJ mol⁻¹)?
1. 100 kJ/mol
2. 80 kJ/mol
3. 60 kJ/mol
4. None of the above
The catalyst lowers the activation energy by 16 kJ mol⁻¹.
A reaction proceeds through several steps in a mechanism. The rate constants for the first, second, third, and fifth steps are k₁, k₂, k₃, and k₅, respectively.
The overall rate constant is given by:
k = (k₂ /k₃) x (k₁/ k₅ )¹ᐟ²
If the activation energies of these steps are 40 kJ mol⁻¹, 60 kJ mol⁻¹, 50 kJ mol⁻¹, and 10 kJ mol⁻¹, respectively.
What is the overall activation energy (in kJ mol⁻¹)?
1. 10
2. 20
3. 25
4. None of the above
k₁ = A₁ e (-Ea₁/RT) and for reaction X → Y, k₂ = A₂ e (-Ea₂/RT),
where A₁ = 108, A₂ = 1010, Ea₁ = 600 cal mol⁻¹, Ea₂ = 1800 cal mol⁻¹, and R = 2 cal K⁻¹ mol⁻¹?
| 1. | \( 1600 \text { K }\) | 2. | \(1200 \times 4.606 \mathrm{~K}\) |
| 3. | \(\dfrac{1200}{4.606} \mathrm{~K}\) | 4. | \(\dfrac{600}{4.606} K\) |
Find the correct relation when the activation energies of two reactions are
(Ea1 and Ea2, where Ea1 > Ea2, and the temperature of the reacting system is increased from (T1) to (T2).
1.
2.
3.
4.
The units of rate constant and rate of reaction are same for :
1. First order reaction
2. Second order reaction
3. Third order reaction
4. Zero order reaction
The plot of log k vs helps to calculate :
1. Energy of activation.
2. Rate constant of reaction.
3. Order of the reaction.
4. Energy of activation as well as the frequency factor.
Which of the following represents the value of the pre-exponential factor (A) for a reaction when the rate constant is K = 1.2×103 mol–1 L s–1 and activation energy Ea = 2.0×102 kJ mol–1, in the limit \(T→∞\)?
1. 2.0 × 102 kJ mol–1
2. 1.2 × 103 mol–1L s–1
3. 1.2 × 103 mol L–1 s–1
4. 2.4 × 103 kJ mol–1L s–1
The rate constant for a reaction 2×10–2 s–1 at 300 K and 8×10–2 s–1 at 340 K. The energy of activation of the reaction is:
1. 14.69 kJ mol–1
2. 29.39 kJ mol–1
3. 44.34 kJ mol–1
4. 22.05 kJ mol–1
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