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

Rate law for the reaction 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 ______. - Chemistry

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प्रश्न

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 ______.

पर्याय

  • the same

  • doubled

  • quadrupled

  • halved

MCQ
रिकाम्या जागा भरा
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उत्तर

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 the same.

Explanation:

The rate of concentration of a reaction does not depend upon the concentrations of the reactants. Hence, it will remain the same. Even if the equation shows the double concentration level, even the rate concentration doubles so it's the same throughout.

Following with the equation \[\ce{A + 2B -> C}\] 

If rate considered as (1) Rate1 = k[A][B]

If rate considered as 2

Then, Rate1 = k[A][2B]

Rate2 = 2Rate1 

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पाठ 4: Chemical Kinetics - Exercises [पृष्ठ ५१]

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एनसीईआरटी एक्झांप्लर Chemistry [English] Class 12
पाठ 4 Chemical Kinetics
Exercises | Q I. 14. | पृष्ठ ५१

संबंधित प्रश्‍न

For a reaction: 

Rate = k

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

(ii) Write the unit of k.


Write two factors that affect the rate of reaction.


For the hydrolysis of methyl acetate in aqueous solution, the following results were obtained :

t/s 0 30 60
[CH3COOCH3] / mol L–1 0.60 0.30 0.15

(i) Show that it follows pseudo first order reaction, as the concentration of water remains constant.

(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.

(Given log 2 = 0.3010, 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


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


Mention the factors that affect the rate of a chemical reaction.


A reaction is first order in A and second order in B. How is the rate affected when the concentrations of both A and B are doubled?


In a reaction between A and B, the initial rate of reaction (r0) was measured for different initial concentrations of A and B as given below:

A/mol L−1 0.20 0.20 0.40
B/mol L−1 0.30 0.10 0.05
r0/mol L−1 s−1 5.07 × 10−5 5.07 × 10−5 1.43 × 10−4

What is the order of the reaction with respect to A and B?


How does calcination differ from roasting?


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.


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


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 of the reaction can be zero or fractional.

Reason: We cannot determine order from balanced chemical equation.


Assertion: The enthalpy of reaction remains constant in the presence of a catalyst.

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.


Use Molecular Orbital theory to determine the bond order in each of species, [He2j+ and [He2]2+?


The conversion of molecules A to B follow second order kinetics. If concentration of A is increased to three times, how will it affect the rate of formation of B?


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]

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)


A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is reduced to half?


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