ECAT Pre Engineering Chemistry Chapter 11 MCQ Test With Answer

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

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

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

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

Optical rotation method is sued when

• Reaction involve ions A
• Change of refractive indices B
• Reactions involving change of optical activity C
• None of the above D

Rate law of an equation is obtained :

• From a balance equation. A
• Can be calculated theoretically as well as determined experimentally. B
• It is only calculated theoretically. C
• Experimentally. 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

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

The experimental relationship between a reaction rate and the concentration of reactants is called

• Order or reaction A
• Rate law B
• Activated complex C
• Molecularity D

The rate of reaction determined at a given time is called

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

It is common observation that rates of chemical reactions differ :

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

In the hydrolysis of CH₃COOC₂H₅the acid produced is

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

All reactions occur in :

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

• 
  A
• 
  B
• 
  C
• 
  D

The rate determining step is the :

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

A substance which increases the rate of a reaction without being consumed during the reaction is called

• An autocatalyst A
• A catalyst B
• A negative catalyst C
• All of these 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 reaction rate is expressed in the units of

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

• Zero A
• 1 B
• 2 C
• 1.5 D

The rate of reaction :

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

When copper is allowed to react with HNO₃, the reaction is slow in the beginning, finally becomes very fast. It is due to the formation of an auto catalyst which is

• Cu(NO₃)₂ A
• CuO B
• O₂ C
• HNO₂ 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

The rate equation for a reaction is Rate =k[A]. what are unit of K ?

• Mole-1 dm³ S^-1

  A

• Mole dm³ S^-1

  B

• Mole dm³

  C

• S^-1

  D

The factor which effect the rate of reaction

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

The catalytic activity of Pt is much higher when

• It is mixed with asbestos A
• It is mixed with Pd B
• It is mixed with arsenic C
• In is made colloidal platinum 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

• Initial concentration of reaction A
• Initial concentration of products B
• Final concentration of products C
• Order of the reaction D

• Homogeneous A
• Heterogeneous B
• Isogeneous C
• None D

In an experiment the concentration of a reactant 'A' is doubled the rate increases four times. If concentration in tripled, then rate increases nint times. Thus the rate is proportional to ______ of concentration of 'A'

• Square root A
• Square B
• Twice C
• Cube 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