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प्रश्न
The value of rate constant of a pseudo first order reaction ______.
पर्याय
depends on the concentration of reactants present in small amount.
depends on the concentration of reactants present in excess.
is independent of the concentration of reactants.
depends only on temperature.
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उत्तर
The value of rate constant of a pseudo first order reaction depends on the concentration of reactants present in excess.
Explanation:
Let's start with what a pseudo-first-order response is.
Although the pseudo-first-order reaction looks to be an order, it belong to another order. it's a second-order reaction because it involves two reactants.
Let's have a look at a reaction.
\[\ce{CH3Br + OH -> CH3OH + Br}\]
So, the rate law for the reaction is
Rate = \[\ce{k[OH][CH3Br]}\]
Rate = \[\ce{k[OH][CH3Br] = k(constant) [CH3Br] = K' [CH3Br]}\]
Only the concentration of \[\ce{CH3Br}\] will change during the reaction and the rate will be determined by the reaction's modifications.
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संबंधित प्रश्न
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.
For a reaction : 
(i) Write the order and molecularity of this reaction.
(ii) Write the unit of k.
For a chemical reaction R → P, the variation in the concentration (R) vs. time (t) plot is given as:
(i) Predict the order of the reaction.
(ii) What is the slope of the curve?
(iii) Write the unit of rate constant for this reaction.
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)
For a reaction, \[\ce{A + B -> Product}\]; the rate law is given by, r = k [A]1/2 [B]2. What is the order of the reaction?
A reaction is first order in A and second order in B. Write the differential rate equation.
How does calcination differ from roasting?
What is the order of a reaction which has a rate expression; Rate = `"k"["A"]^(3/2)["B"]^1`?
Rate law for the reaction \[\ce{A + 2B -> C}\] is found to be Rate = k [A][B]. Concentration of reactant ‘B’ is doubled, keeping the concentration of ‘A’ constant, the value of rate constant will be ______.
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 |
Why molecularity is applicable only for elementary reactions and order is applicable for elementary as well as complex reactions?
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) |  |
Assertion: Order of the reaction can be zero or fractional.
Reason: We cannot determine order from balanced chemical equation.
Assertion: Order and molecularity are same.
Reason: Order is determined experimentally and molecularity is the sum of the stoichiometric coefficient of rate determining elementary step.
Use Molecular Orbital theory to determine the bond order in each of species, [He2j+ and [He2]2+?
The role of a catalyst is to change
For reaction 2A + B → BC + D which of the following does not Express the reaction rates
Read the following passage and answer the questions that follow:
|
The rate of reaction is concerned with decrease in the concentration of reactants or increase in the concentration of products per unit of time. It can be expressed as instantaneous rate at a particular instant of time and average rate over a large interval of time. A number of factors such as temperature, concentration of reactants, catalyst affect the rate of reaction. Mathematical representation of rate of a reaction is given by rate law: Rate = k[A]x [B]y x and y indicate how sensitive the rate is to change in concentration of A and B. Sum of x + y gives the overall order of a reaction. |
- What is the effect of temperature on the rate constant of a reason? [1]
- For a reaction \[\ce{A + B → Product}\], the rate law is given by, Rate = k[A]2 [B]1/2. What is the order of the reaction? [1]
- How order and molecularity are different for complex reactions? [1]
- A first-order reaction has a rate constant 2 × 10–3 s–1. How long will 6 g of this reactant take to reduce to 2 g? [2]
OR
The half-life for radioactive decay of 14C is 6930 years. An archaeological artifact containing wood had only 75% of the 14C found in a living tree. Find the age of the sample.
[log 4 = 0.6021, log 3 = 0.4771, log 2 = 0.3010, log 10 = 1] [2]
Assertion (A): Order of reaction is applicable to elementary as well as complex reactions.
Reason (R): For a complex reaction, molecularity has no meaning.
