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

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

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प्रश्न

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

पर्याय

  • The order of a reaction can be a fractional number.

  • Order of a reaction is experimentally determined quantity.

  • The order of a reaction is always equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction.

  • The order of a reaction is the sum of the powers of molar concentration of the reactants in the rate law expression.

MCQ
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उत्तर

The order of a reaction is always equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction.

Explanation:

In rate law expression, the order of reaction is equal to the sum of the power of concentration of the reactants.

\[\ce{xA + yB -> zC}\]

r = k(A)x (B)y

Order x + y

The order of the reactions can also be a fraction. In a balanced chemical equation, the order of reaction may or may not be equal to the total of the stoichiometric coefficient of the reactants.

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पाठ 4: Chemical Kinetics - Exercises [पृष्ठ ४९]

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एनसीईआरटी एक्झांप्लर Chemistry Exemplar [English] Class 12
पाठ 4 Chemical Kinetics
Exercises | Q I. 9. | पृष्ठ ४९

संबंधित प्रश्‍न

Define “zero order 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?


What is the order of a reaction which has a rate expression; Rate = `"k"["A"]^(3/2)["B"]^1`?


Molecularity of a reaction _____________.


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

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 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 molecularity is applicable only for elementary reactions and order is applicable for elementary as well as complex reactions?


Why can we not determine the order of a reaction by taking into consideration the balanced chemical equation?


Assertion: Order of the reaction can be zero or fractional.

Reason: We cannot determine order from balanced chemical equation.


A catalyst in a reaction changes which of the following?


The rate of a chemical reaction double for every 10° rise in temperature. If the temperature is raised. by 50°C, the rate of relation by about:-


For a reaction 1/2 A ⇒ 2B, rate of disappearance of A is related 't o the appearance of B by the expression:


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]
    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.


Which of the following statement is true?


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