ECAT Pre Engineering Chemistry Chapter 11 MCQ Test With Answer

In the reaction of oxalic acid with KMnO₄and H₂SO₄is slow at the beginning but after sometimes the reaction becomes faster due to

• Formation of MnSO₄which acts as 'Auto catalyst A
• Formation of CO₂which acts as 'Auto catalyst B
• Formation of K₂SO₄which acts as 'Auto catalyst C
• Evolution of O₂gas which acts as 'Auto catalyst D

Which of the following may affect the rate constant (k) fro a reaction :

• Change in concentration. A
• Change in pressure. B
• Change in pH. C
• Change in temperature. D

• Rate = k[FeCl₃] [Kl]² A
• Rate = k[Fe⁺³][Cl^-1] [Kl] B
• Rate = k[Fe⁺³] [Cl^-1][K;] C
• Rate = k[Kl]³[FeCl₃]° D

The rate of reaction :

• Decreases as the reaction proceeds A
• Increases as the reaction proceeds B
• May decrease or increase reaction proceeds C
• Remains same as the reaction proceeds D

The value of activation energy Ea of a reaction can be determined from the value of slope of the straight line obtained by plotting a graph between 1/T and log k. the value of Ea is equal to

• Slope A
• 1/Slope B
• Slope x R C
• Slope x 2.303 R D

Which of the following is not affected by light

• 
  A
• 
  B
• 
  C
• 
  D

• Small change in concentration of product A
• Small time internal B
• Co-efficient of the reactant C
• Co-efficient of the product D

The rate determining step is the :

• Slowest step. A
• Fastest step. B
• Moderate step. C
• Both (a) and (b). D

The unit of rate constant is the same as that of the rate of reaction in :

• First order reaction. A
• Second order reaction. B
• Zero order reaction. C
• Third order reaction. D

In the manufacture of NH₃by Haber's process catalyst used is iron its catalytic efficiency is poisoned by

• Presence of Al₂O₃ A
• Presence of Cr₂O₃ B
• MnO₂ C
• CO present with H₂gas D

When we perform the same reaction by taking two different initial concentrations of a reactant for a second order reaction then

• Reaction becomes exothermic A
• Energy of activation is different B
• Mechanism of reaction is changed C
• Half life period is changed D

The rate of reaction determined at a given time is called

• Average rate A
• Instantaneous rate B
• Specific rate C
• Overall rate D

In the expression rate = K [A]^a[B]^bK is

• The order of reaction A
• The speed of reaction B
• The specific rate constant C
• The overall order of reaction D

The chemical method used for determination of rate of reaction is

• Spectroscopic A
• Conductiometric B
• Refractometric C
• Titration D

In the hydrolysis of CH₃COOC₂H₅the acid produced is

• Inhibitor A
• Catalyst B
• Auto catalyst C
• None of above D

The rate of reaction determined at a given time is called

• Average rate A
• Instantaneous rate B
• Specific rate C
• Overall rate D

In zero order reaction, the rate is independent of :

• Temperature of reaction A
• Concentration ofreactants B
• Concentration of products C
• None of these. D

To determine the rate of reaction chemically a graphical method is applied. A graph is plotted between the amount or reactant decomposed or product formed against the time. The rate d_x/d_tat any time is equal to

• k A
• Tangentθ B
• 1/a, a is initial conc. C
• 1/a² D

A white precipitate ofsilver chlorideimmediately formed on additionof :

• Silver nitrate solution to sodium chloride solution. A
• Silver chloride solution to sodium nitrate solution. B
• Silver nitrate solution to potassium chloride solution C
• Silver nitrate solution to hydrogen chloride solution. D

The sum of the exponents of the conc. terms in the rate equation is called

• Rate of reaction A
• Order of reaction B
• Specific rate constant C
• Average rate D

The rate of reaction is denoted by

• dc/dp A
• dc/ac B
• dc/dT C
• dc/dt D

When initial concentration of reactants an order of reaction is given, then its half life period can be calculated by the equation

• 
  A
• 
  B
• 
  C
• 
  D

Which statement about Arrhenius equation is incorrect

• Factor 'A' called Arrhenius constant depends upon collision frequency of reactants A
• Rate of reaction increase by increasing temperature B
• Rate constant k is increased C
• Activation energy Ea is decreased by rise in temperature D

The reaction rate is expressed in the units of

• mol dm^-3S^- A
• mol dm^-3 B
• mol dm^-3N^- C
• dm^-3S^- D

With increases in temperature of 10 K of the reacting gases the rate of reaction is doubled because

• Increase in number of collisions A
• Number of molecules having energy more than Ea is doubled B
• Increase in order of reaction C
• Increase in surface area D

The rate of reaction between two specific time intervals is called

• Instantaneous rate A
• Average rate B
• Specific rate C
• Ordinary rate D

The rate of reaction b/w two specific time intervals is called :

• Instantaneous rate of reaction. A
• Average rate of reaction. B
• Rate of a reaction. C
• Minimum rate of a reaction. D

All reactions occur in :

• A single step. A
• A series of steps B
• Two steps. C
• Both (a) and (b) D

Platinum is poisoned by

• Arsenic A
• Silver B
• Argon C
• Zinc D

Value of rate constant k is specific for a reaction, and varies from reaction to reaction. The value of k of a reaction changes with

• Time A
• Temperature B
• Concentration of reactants C
• Order of reaction D