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कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

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

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प्रश्न

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.

टीपा लिहा
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उत्तर

(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.

Explanation:

For any unimolecular reaction, only one reactant is involved in rate determining step and the order and molecularity of rate determining or slowest step are one.

A → B

Rate = `k[A]`

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पाठ 4: Chemical Kinetics - Exercises [पृष्ठ ५३]

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एनसीईआरटी एक्झांप्लर Chemistry Exemplar [English] Class 12
पाठ 4 Chemical Kinetics
Exercises | Q II. 23. | पृष्ठ ५३

संबंधित प्रश्‍न

Define “zero order reaction”.


What is pseudo first order reaction? Give one· example of it.


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Time / sec               Totalpressure / atm

0                              0.30

300                          0.50

Calculate the rate constant

(Given: log 2 = 0.301, log3 = 0.4771, log 4 = 0.6021)


From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.

\[\ce{3NO_{(g)} -> N2O_{(g)}}\] Rate = k[NO]2


A reaction is first order in A and second order in B. How is the rate affected on increasing the concentration of B three times?


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.


Write the principle behind the following methods of refining:

Hydraulic washing


Define the following term:

Pseudo first-order reaction


Rate of reaction for the combustion of propane is equal to:

\[\ce{C3H8_{(g)} + 5O2_{(g)} -> 3CO2_{(g)} + 4H2O_{(g)}}\]


The value of rate constant of a pseudo first order reaction ______.


Consider the reaction A ⇌ B. The concentration of both the reactants and the products varies exponentially with time. Which of the following figures correctly describes the change in concentration of reactants and products with time?


For which type of reactions, order and molecularity have the same value?


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?


Assertion: Order and molecularity are same.

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Reason: A catalyst participating in the reaction, forms different activated complex and lowers down the activation energy but the difference in energy of reactant and product remains the same.


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The role of a catalyst is to change


For the reaction, \[\ce{A +2B → AB2}\], the order w.r.t. reactant A is 2 and w.r.t. reactant B. What will be change in rate of reaction if the concentration of A is doubled and B is halved?


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.
When a sequence of elementary reactions gives us the products, the reaction is called complex reaction. Molecularity and order of an elementary reaction are same. Zero-order reactions are relatively uncommon but they occur under special conditions. All natural and artificial radioactive decay of unstable nuclei takes place by first-order kinetics.

  1. What is the effect of temperature on the rate constant of a reason?    [1]
  2. 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]
  3. How order and molecularity are different for complex reactions?    [1]
  4. 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]
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    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.
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Which of the following statement is true?


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