ECAT Pre Engineering Chemistry Chapter 11 MCQ Test With Answer

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

In the rate equation when the concentration of reactants are unity, then rate is equal to

• Instantaneous rate A
• Average rate B
• Active mass of products C
• Specific rate constant 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

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

• 3 A
• 2 B
• 1 C
• 1 D

With increases of 10°C temperature the rate of reactiondoubles. This increase in rate of reactionis due to :

• Decrease in activation energy or reaction. A
• Decrease in number of collisions between reactant molecules. B
• Increase in activation energy of reactants. C
• Increase in number of effective collisions D

The chemical method used for determination of rate of reaction is

• Spectroscopic A
• Conductiometric B
• Refractometric C
• Titration 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

With the progressive of the reaction the slope of the curve between concentration of product and time

• Gradually becomes more steep A
• Gradually becomes less steep B
• No change occurs in slope C
• None of these occurs 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

• 1st order A
• 2nd order B
• Zero order C
• 3rd order D

• 
  A
• 
  B
• 
  C
• 
  D

• Measuring pH A
• Measuring density B
• Titration against standard NaOH C
• Titration against standard KMnO₄solution 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

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

When the rate of reaction is entirely independent of the conc. of reaction molecules then order of reaction is

• Zero A
• First B
• Second C
• Third 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

In zero order reaction, the rate is independent of :

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

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

If half life period of a reaction is independent of the concentration of the reactants, then the reaction is

• Zero order A
• First order B
• Second order C
• Order is in fraction D

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

• Order A
• Molecularity B
• Rate constant C
• Rate law 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 example of a photo chemical reaction is photosynthesis has order of reaction :

• 1 A
• 2 B
• 0 C
• 3 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

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

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

The factor which effect the rate of reaction

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

Platinum is poisoned by

• Arsenic A
• Silver B
• Argon C
• Zinc 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 rate determining step is the :

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

By the use of catalysis the energy of activation is

• Decreased A
• Increased B
• Not affected C
• None D