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

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

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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.

MCQ
रिकाम्या जागा भरा
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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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पाठ 4: Chemical Kinetics - Exercises [पृष्ठ ५२]

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एनसीईआरटी एक्झांप्लर Chemistry [English] Class 12
पाठ 4 Chemical Kinetics
Exercises | Q I. 19. | पृष्ठ ५२

संबंधित प्रश्‍न

Define “zero order reaction”.


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, \[\ce{A + B -> Product}\]; 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


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 on increasing the concentration of B three times?

 


Define the following term:

Pseudo first-order reaction


Define the following terms:

Half-life period of reaction (t1/2).


What is the order of a reaction which has a rate expression; Rate = `"k"["A"]^(3/2)["B"]^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 ______.


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?


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.


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.


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?


A drop of solution (volume 0.05 ml) contains 3.0 × 10-6 mole of H+. If the rate constant of disappearance of H+ is 1.0 × 107 mole l-1s-1. It would take for H+ in drop to disappear in ______ × 10-9s.


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]


Which of the following statement is true?


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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