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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? - Chemistry

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प्रश्न

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?

संख्यात्मक
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उत्तर

Rate of reaction, R = k [A]2

If the concentration of the reactant is reduced to half:

If [A] = `1/2` A,

rate = `k (A/2)^2`

= `1/4` kA2

Change in rate of reaction = `(1/4 kA^2) : kA^2`

= `1/4 : 1`

Therefore, the reaction rate decreases to one-fourth its original value.

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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 3.6 (ii) | पृष्ठ ८५

संबंधित प्रश्‍न

Define “zero order reaction”.


Write two factors that affect the rate of reaction.


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. Write the differential rate equation.


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?


How does calcination differ from roasting?


Define the following term:

Pseudo first-order reaction


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 ______.


The value of rate constant of a pseudo first order 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?


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


For a reaction R → p the concentration of reactant change from 0.03 m to 0.02 m in minute, calculate the average rate of the reaction using the unit of second.


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?


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 reaction 2A + B → BC + D which of the following does not Express the reaction rates


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?


Identify the order of reaction from the following unit for its rate constant:

L mol–1 s–1


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]

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