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

Compounds ‘A’ and ‘B’ react according to the following chemical equation. A(g)+2B(g)⟶2C(g)Concentration of either ‘A’ or ‘B’ were changed keeping the

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प्रश्न

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 L¹
Initial
concentration
of [B]/mol L¹
Initial rate of
formation of
[C]/mol L¹ s¹
1. 0.30 0.30 0.10
2. 0.30 0.60 0.40
3. 0.60 0.30 0.20

पर्याय

  • Rate = k[A]2[B]

  • Rate = k[A][B]2

  • Rate = k[A][B]

  • Rate = k[A]2[B]0 

MCQ
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उत्तर १

Rate = k[A][B]

Explanation:

Rate = k[A]x[B]y

When concentration of B is doubled keeping the concentration of A constant, the rate of formation of C increases by a factor of four. This indicates that the rate of reactions depends upon the square of concentration of B. When concentration of A is doubled, the rate of formation of C also doubles from the initial value. This shows that the rate depends on first power of concentration of A. Hence Rate= k[A]x[B]y.

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उत्तर २

Let order of A and B be x and y.

r = k [A]x [B]y

0.1 = k (0.3)x (0.3)y  ...(1)

0.4 = 0.1 = k (0.3)x (0.6)y   ...(2)

0.2 = 0.1 = k (0.6)x (0.3)y   ...(3)

Divide 2 by 1

`0.4/0.1 = (0.6)^"y"/(0.3)^"y"`

Divide 3 by 1

`0.2/0.1 = (0.6)^"x"/(0.3)^"x"`

Hence Rate law is

r = k [A]1 [B]2

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पाठ 4: Chemical Kinetics - Exercises [पृष्ठ ५१]

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एनसीईआरटी एक्झांप्लर Chemistry Exemplar [English] Class 12
पाठ 4 Chemical Kinetics
Exercises | Q I. 17. | पृष्ठ ५१

संबंधित प्रश्‍न

For a reaction: 

Rate = k

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

(ii) Write the unit of k.


For the first order thermal decomposition reaction, the following data were obtained:

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)


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.


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?


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


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


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?


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

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


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.


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 ______.


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.


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


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.


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.


The number of molecules of the reactants taking part in a single step of the reaction is indicative of ______.


On heating compound (A) gives a gas (B) which is constituent of air. The gas when treated with H2 in the presence of catalyst gives another gas (C) which is basic in nature, (A) should not be ______.


For a chemical reaction starting with some initial concentration of reactant At as a function of time (t) is given by the equation,

`1/("A"_"t"^4) = 2 + 1.5 xx 10^-3` t

The rate of disappearance of [A] is ____ × 10-2 M/sec when [A] = 2 M.

[Given: [At] in M and t in sec.]
[Express your answer in terms of 10-2 M /s]
[Round off your answer if required]


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)


Which of the following statement is true?


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