ECAT Pre Engineering Chemistry Chapter 11 MCQ Test With Answer

• Three times A
• Six times B
• Nine times C
• Two times D

In thermal decomposition of N₂O the half life period for two different initial concentrations of N₂O are

(i) 255 second for initial N₂O 290 mm Hg

(ii) 212 second for initial N₂O 360 mm Hg then it is

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

The rate of reaction determined at a given time is called

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

The addition of a catalyst to a reaction changes the

• Enthalpy A
• Entropy B
• Nature of reactants C
• Energy of activation D

Dilatometric method is used for rate determination when

• Reactions involving change of optical A
• Reactions involving change of optical activity B
• Reactions involving small volume change C
• None of above D

Hydrogenation of vegetable oils is accelerated by Ni catalyst. The catalytic activity of Bi is increased by a promoter of activator which is

• Na and K A
• Na and Hg B
• Hg and Zn C
• Cu and Te D

Which of the following will affect the rate :

• First step of reaction. A
• Last step of reaction. B
• Rate determining step. C
• Fastest step. D

Which of the following factors does not influenced the rate of reaction

• Concentration of the reaction A
• Nature of the reactants B
• Molecularity of the reaction C
• Temperature D

The factor which effect the rate of reaction

• Nature of reactants A
• Surface area B
• Light C
• All of the above D

Refrectrometric method is used when

• Reactions involving absorption of I.R. or U. V A
• Reactions involving change of refractive index B
• Reactions involving ions C
• Change of optical activity D

The number of atoms or molecules whose concentrations determine the rate of the reaction is called

• Molecularity A
• Order B
• Rate of reaction C
• Rate constant D

The rate constant k of a reaction activation energy Ea and temperature are related by Arrhenius in the form of an equation which is

• 
  A
• 
  B
• 
  C
• 
  D

Activation energy is the difference of energy between the energy of the reactant and

• The product A
• The activated complex B
• Both a and b C
• None of these 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

It is common observation that rates of chemical reactions differ :

• Greatly. A
• A little bit. B
• Moderately. C

Hydrolysis of ethyl-acetate (ester) has order of reaction :

• 3 A
• 2 B
• 1 C
• 1 D

If the rate of decay of radioactive isotope decreases from 200 cpm to 25 cpm after 24 hours, what is its half life :

• 8 hours A
• 6 hours B
• 4 hours C
• 3 hours D

The unit rate of constan K ismole^-1 dm³S^-1for a chemical reaction, the order of reaction is :

• 3 A
• 2 B
• 1 C
• 0 D

If a reactant or product of a reaction absorbs radiation, then physical method for determining the rate of reaction is

• Spectrometry A
• Refractometry B
• Conductivity measurement C
• Optical method D

In the hydrolysis of CH₃COOC₂H₅the acid produced is

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

In exothermic reaction decrease in potential energy of the products will result in

• Decreases in kinetic energy of the particles A
• Increases in kinetic energy of the particles B
• No change in kinetic energy C
• Decreases in activation energy 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

Which statement is true about order of reaction :

• Order of reaction can only be determined by an experiment. A
• Order of reaction can be determined from a balance equation only. B
• Order of reaction increase by increasing temperature. C
• Order of reaction must be in whole number and not in fraction. 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

For effective collisions the molecules slow down before collision and their kinetic energy decreases which results in increase in their

• Activation energy A
• Average energy B
• Potential energy C
• Collisions frequency D

______ are called biocatalysts

• Organic acids A
• Organic bases B
• Enzymes C
• All D

A zero order reaction is one in which :

• Rate is not affected by changing concentration of reactants. A
• concentration of reactants do not change with the passage of time. B
• Reactants do not react. C
• One reactants in large excess. D

• 2 A
• 3 B
• 4 C
• 9 D

• Diastase A
• Lipase B
• Inverters C
• Zymase 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