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प्रश्न
For which type of reactions, order and molecularity have the same value?
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उत्तर
For an elementary reaction, the order is the same as molecularity. Elementary reactions are those reactions which occur in a single step.
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संबंधित प्रश्न
In a first order reaction x → y, 40% of the given sample of compound remains unreacted in 45 minutes. Calculate rate constant of the reaction.
A → B is a first order reaction with rate 6.6 × 10-5m-s-1. When [A] is 0.6m, rate constant of the reaction is
- 1.1 × 10-5s-1
- 1.1 × 10-4s-1
- 9 × 10-5s-1
- 9 × 10-4s-1
What is pseudo first order reaction? Give one· example of it.
Write molecularity of the following reaction:
2NO(g)+O2(g)→2NO2(g)
The following data were obtained during the first order thermal decomposition of SO2Cl2 at a constant volume :
SO2Cl2 (g) → SO2 (g) + Cl2 (g)
| Experiment | Time/s–1 | Total pressure/atm |
| 1 | 0 | 0.4 |
| 2 | 100 | 0.7 |
Calculate the rate constant.
(Given : log 4 = 0.6021, log 2 = 0.3010)
From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.
\[\ce{CH3CHO_{(g)} -> CH4_{(g)} + CO_{(g)}}\] Rate = k [CH3CHO]3/2
From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.
\[\ce{C2H5Cl_{(g)} -> C2H4_{(g)} + HCl_{(g)}}\] Rate = k [C2H5Cl]
A reaction is first order in A and second order in B. Write the differential rate equation.
The decomposition of N2O5(g) at 320K according to the following equation follows first order reaction:
`N_2O_(5(g))->2NO_(2(g))+1/2O_(2(g))`
The initial concentration of N2O5(g) is 1.24 x 10-2 mol. L-1 and after 60 minutes 0.20x10-2 molL-1. Calculate the rate constant of the reaction at 320K.
Compounds ‘A’ and ‘B’ react according to the following chemical equation.
\[\ce{A(g) + 2B(g) -> 2C(g)}\]
Concentration of either ‘A’ or ‘B’ were changed keeping the concentrations of one of the reactants constant and rates were measured as a function of initial concentration. 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]/mol L–¹ |
Initial rate of formation of [C]/mol L–¹ s–¹ |
| 1. | 0.30 | 0.30 | 0.10 |
| 2. | 0.30 | 0.60 | 0.40 |
| 3. | 0.60 | 0.30 | 0.20 |
In any unimolecular reaction:
(i) only one reacting species is involved in the rate determining step.
(ii) the order and the molecularity of slowest step are equal to one.
(iii) the molecularity of the reaction is one and order is zero.
(iv) both molecularity and order of the reaction are one.
For a complex reaction:
(i) order of overall reaction is same as molecularity of the slowest step.
(ii) order of overall reaction is less than the molecularity of the slowest step.
(iii) order of overall reaction is greater than molecularity of the slowest step.
(iv) molecularity of the slowest step is never zero or non interger.
For a general reaction A → B, plot of concentration of A vs time is given in figure. Answer the following question on the basis of this graph.
(i) What is the order of the reaction?
(ii) What is the slope of the curve?
(iii) What are the units of rate constant?
Match the graph given in Column I with the order of reaction given in Column II. More than one item in Column I may link to the same item of Column II.
| Column I | Column II | |
| (i) |  |
|
| (ii) |  |
(a) 1st order |
| (iii) |  |
(b) Zero-order |
| (iv) |  |
The rate constant for the reaction \[\ce{2H2O5 -> 4NO2 + O2}\] is 30 × 10–5 sec–1. if the rate is 204 × 10–5 mol L–1 S–1, then the concentration of N2O5 (in mol–1) is-
For a first order A → B, the reaction rate at reactant concentration of 0.01 m is found to be 2.0 × 10–5. The half-life period of reaction.
A flask contains a mixture of compounds A and B. Both compounds decompose by first-order kinetics. The half-lives for A and B are 300 s and 180 s, respectively. If the concentrations of A and B are equal initially, the time required for the concentration of A to be four times that of B (in s) is ______. (Use ln 2 = 0.693)
Assertion (A): Order of reaction is applicable to elementary as well as complex reactions.
Reason (R): For a complex reaction, molecularity has no meaning.
