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

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?

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प्रश्न

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?

A reaction is of first order with respect to reactant [A] and second order with regard to reactant [B]. What is the effect on rate of reaction when concentration of [B] three times?

संख्यात्मक
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उत्तर

If the concentration of B is increased three times, then:

`-(d[R])/dt` = k[A][3B]2

= 9k[A][B]2

∴ The reaction rate will increase by a factor of 9.

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पाठ 3: Chemical Kinetics - Exercises [पृष्ठ ८५]

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एनसीईआरटी Chemistry Part 1 and 2 [English] Class 12
पाठ 3 Chemical Kinetics
Exercises | Q 3.9 (ii) | पृष्ठ ८५

संबंधित प्रश्‍न

A reaction is second order in A and first order in B.

(i) Write the differential rate equation.

(ii) How is the rate affected on increasing the concentration of A three times?

(iii) How is the rate affected when the concentrations of both A and B are doubled?

 


For a reaction A + B ⟶ P, the rate is given by

Rate = k [A] [B]2

What is the overall order of reaction if A is present in large excess?


For a reaction : 

(i) Write the order and molecularity of this reaction.

(ii) Write the unit of k.


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


For the reaction:

\[\ce{2A + B -> A2B}\] 

the rate = k[A][B]2 with k = 2.0 × 10−6 mol−2 L2 s−1. Calculate the initial rate of the reaction when [A] = 0.1 mol L−1, [B] = 0.2 mol L−1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L−1.


Consider a first order gas phase decomposition reaction given below :
\[\ce{A(g) -> B(g) + C(g)}\]
The initial pressure of the system before decomposition of A was pi. After lapse of time ‘t’, total pressure of the system increased by x units and became ‘pt’ The rate constant k for the reaction is given as ______.


Which of the following statements is not correct about order of a reaction.


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


In a reaction if the concentration of reactant A is tripled, the rate of reaction becomes twenty seven times. What is the order of the reaction?


Why is the probability of reaction with molecularity higher than three very rare?


Why does the rate of any reaction generally decreases during the course of the reaction?


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 role of a catalyst is to change


In the presence of a catalyst, the heat evolved or absorbed during the reaction.


For a reaction \[\ce{Cl2l(g) + 2No(g) -> 2NaCl(g)}\] the rate law is expressed as rate= K[Cl2] [No]2 what is the order of the reaction?


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]
    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.


Higher yield of NO in \[\ce{N2(g) + O2 <=> 2NO(g)}\] can be obtained at:

[ΔH of the reaction = +180.7 kJ mol−1]

  1. higher temperature
  2. lower temperature
  3. higher concentration of N2
  4. higher concentration of O2

Choose the correct answer from the options given below:


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