Find the minimum possible value of activation energy, Eₐ, for an endothermic reaction having enthalpy change ΔH.

1. Less than ΔH

2. Zero

3. More than ΔH

4. Equal to ΔΗ

In the formation of sulphur trioxide by the contact process:

2SO₂(g) + O₂(g) $\to$2SO₃(g)

The rate of reaction is expressed as $\frac{\mathrm{d}\left[{\mathrm{O}}_2\right]}{\mathrm{dt}}$= 2.5×10^–4 mol L^–1 sec^–1. Find the rate of disappearance of SO₂ :

1. 5.0×10^–4 mol L^–1sec^–1

2. 2.5×10^–4 mol L^–1sec^–1

3. 3.75×10^–4 mol L^-1sec^–1

4. 50.0×10^–4 mol L^–1sec^–1

A first order reaction complete 40% in 20 minutes. In how much time it is completed 90% of its original amount?

1. 45 min

2. 60 min 

3. 75 min

4. 90 min

The dissociation of H₂O₂ is a first order reaction. The half life for '16 V H₂O₂ is 30 min, calculate the time at which the solution is 1V H₂O₂ ?

1. 120 min.

2. 90 min.

3.  60 min.

4.  150 min.

If the activation energy is 65 kJ then the reaction at 25°C is .......times fast as compared to 0°C :-

1. 2 times

2. 5 times

3. 11 times

4. 16 times

When temperature is increased from 27$°$C to 127$°$C, rate of reaction becomes doubled, then E_a will be?

1. 1.66 kcal.

2. 3.32 kcal.

3. 5.33 kcal.

4. 6.64 kcal.

A 1 L solution of 2 M acetic acid is mixed with a 1 L solution of 3 M ethyl alcohol.
The following elementary reaction takes place:

CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O

If 1 L of water is added separately to each solution before mixing,
the initial rate of reaction becomes:
 

1. Four (4) times the original rate

2. Two (2) times the original rate

3. Half (0.5) of the original rate

4. One-fourth (0.25) of the original rate

For a certain reaction, 10% of the reactant dissociates in 1 hour, 20% of the reactant dissociates in 2 hours, 30% of the reactant dissociates in 3 hours. Then the units of the rate constant is:

1.  hour^-1

2.  mol L^-1 hr^-1

3.  mol L^-1 sec^-1

4.  mol L sec^-1

Which of the following plots correctly shows how the concentration of A changes with time for a first-order reaction A → products?
 

1.		2.
3.		4.

Two reactions of the same order have equal Pre-exponential factors but their activation energies differ by 24.9 kJ/mol. Calculate the ratio between the rate constants (K₁/K₂) these reactions at 27°C :

1. 2.2 × 10⁴

2. 1/2 × 10^-4

3. 1/2 × 10⁴

4. 2.2 × 10^-4