For a reaction A Product, rate law is . The concentration of A left after time t when is:
1.
2.
3.
4.
For an exothermic chemical process occurring in two steps as;
(i) A+BX(Slow)
(ii) XAB (Fast)
The progress of the reaction can be best described by:
1. | 2. | ||
3. | 4. | All of the above. |
If 'I' is the intensity of absorbed light and 'c' is the concentration of AB for the photochemical process AB + hv→ AB *, the rate of formation of AB * is directly proportional to:
1. c
2. I
3. I2
4. cI
The rate of disappearance of SO2 in the reaction; 2S02 +02 → 2S03 is 1.28 x10-3g/sec. Then the rate of formation of SO3 is:
1. 0.64 x10-3 g/sec.
2. 0.80x10-3 g/sec
3. 1.28 x10-1 g/sec
4. 1.60 x10-3 g/sec
The rate constant of a second-order reaction is
10–2 mol–1 litre s–1 . The rate constant expressed in cc molecule–1 min–1 is:
1. 9.96 × 10–22
2. 9.96 × 10–23
3. 9.96 × 10–21
4. 1.004 × 10–24
For a given reaction, the presence of a catalyst reduces the energy of activation by 2 kcal at 27 oC. The rate of reaction will be increased by:
1. 20 times
2. 14 times
3. 28 times
4. 2 times
3A C + D, For this reaction it is observed that when initial concentration of A is 10 mole/lit then t1/2 value of this reaction is 40 min and when initial concentration of A is 20 mole / lit, t1/2 value has been changed into 20 min. Which of the following is true?
(1) The reaction is bimolecular reaction
(2) This reaction is an example of radioactive disintegration
(3) The reaction is of 1st order
(4) The order of the reaction is two
A gaseous reaction A2(g) → B(g) + (g) shows increase in pressure from 100 mm to 120 mm in 5 minutes. The rate of disappearance of A2 will be :
1. | 4 mm min-1 | 2. | 8 mm min-1 |
3. | 16 mm min-1 | 4. | 2 mm min-1 |
When temperature is increased from 27C to 127C, rate of reaction becomes doubled, then Ea will be?
1. 1.66 kcal.
2. 3.32 kcal.
3. 5.33 kcal.
4. 6.64 kcal.
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
The rate constant for a chemical reaction that takes place at 500 K is expressed as K = A e-1000. The activation energy of the reaction will be:
1. 100 cal/mol
2. 1000 kcal/mol
3. 104 kcal/mol
4. 106 kcal/mol
Mechanism of a hypothetical reaction
is given below
(i)
(ii)
(iii)
The overall order of the reaction will be
1. 1
2. 2
3. 0
4. 1.5
The rate constant of the reaction A B is 0.6 x 10-3 molar per second. If the
concentration of A is 5 M then concentration of B after 20 min is
1. 1.08 M
2. 3.60 M
3. 0.36 M
4. 0.72 M
If the rate of reaction doubles when the temperature is raised from 20 °C to 35 °C, then the activation energy for the reaction will be :
(R = 8.314 J mol-1 K-1)
1. 342 kJ mol-1
2. 269 kJ mol-1
3. 34.7 kJ mol-1
4. 15.1 kJ mol-1
The rate constants k1 and k2 for two different reactions are 1016 e-2000/T and 1015 e-1000/T , respectively. The temperature at which k1=k2 is:
(1) 1000 K
(2)
(3) 2000K
(4)
The following equilibrium constants are given:
The equilibrium constant for the oxidation of NH3 by oxygen to give NO is:
(1)
(2)
(3)
(4)
Assertion : For a reaction
activation energy is 4135 J/mol.
Reason : Since for any reaction, values of rate constant at two different temp is same therefore
activation energy of the reaction is zero.
The elementary reaction A + B products has k = 2 × 10-5 M-1 s-1 at a temperature of C. Several experimental runs are carried out using stoichiometric proportion. The reaction has a temperature coefficient value of 2.0. At what temperature should the reaction be carried out if, in spite of halving the concentrations, the rate of reaction is desired to be 50 % higher than in the previous run?
(Given
1.
2.
3.
4.
For the reaction The rate is given of
Rate= what percentage of R-X Reaction by mechanism when
1. 96.1%
2. 3.9%
3. 80%
4. 20%
For a certain reaction involving a single reactant, it is found that is constant where is the initial concentration of the reactant and T is the half-life. What is the order of the reaction ?
(1) 1
(2) Zero
(3) 2
(4) 3
The high temperature ( 1200K) decomposition of (g) occurs as follows as per simultaneous 1st order reactions.
What would be the % of by mole in the product mixture (excluding)?
1.
2.
3.
4. it depends on the time
For the first order reaction = x × the value of ‘x’ will be
(A) 10
(B) 6
(C) 3
(D) 2
A catalyst lowers the activation energy of a reaction from 20 kJ mol–1 to 10 kJ mol-1. The temperature at which the uncatalysed reaction will have the same rate as that of the catalysed at 27 oC will be:
1. \(-123\ ^{\circ}C\)
2. \(-327\ ^{\circ}C\)
3. \(327\ ^{\circ}C\)
4. \(23\ ^{\circ}C\)
A catalyst lowers the activation energy of a reaction from . The temperature at which the uncatalysed reaction will have the same rate as that of the catalysed at is :
(1)
(2)
(3) - 327
(4)
The rate of reaction triples when the temperature changes from \(20{ }^{\circ} \mathrm{C} \text { to } 50^{\circ} \mathrm{C}\). The energy of activation for the reaction will be:
1. | \(28.81 \mathrm{~kJ} \mathrm{~mol}^{-1} \) | 2. | \(38.51 \mathrm{~kJ} \mathrm{~mol}^{-1} \) |
3. | \(18.81 \mathrm{~kJ} \mathrm{~mol}^{-1} \) | 4. | \(8.31 \mathrm{~kJ} \mathrm{~mol}^{-1}\) |
What is the percentage of the reactant molecules crossing over the energy barrier at 325 K?
Given that
1. | 80.62 % | 2. | 85.23 % |
3. | 89.27 % | 4. | None of the above |
For the reaction, C2H5I + OH- → C2H5OH + I- the rate constant was found to have a value of 5.03 × 10-2 moI-1 dm3 s-1 at 289 K and 6.71 mol-1 dm3 s-1 at 333 K.
The rate constant at 305 K will be:
The rate constant of a certain first order reaction increases by 11.11% per degree rise of temperature at . By what % will it increase at 127o C, assuming constancy of activa-
tion energy over the given temperature range ?
(A) 5.26%
(B) 5.62%
(C) 6.25%
(D) 7.33%