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

Which of the following is not affected by light

• 
  A
• 
  B
• 
  C
• 
  D

It is common observation that rates of chemical reactions differ :

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

The rate determining step is the :

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

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

In the hydrolysis of CH₃COOC₂H₅the acid produced is

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

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

Which statement is not correct

• Enzymes catalyst a specific reaction A
• Enzymes show catalytic activity at a specific temperature B
• The catalytic activity of enzymes is stopped if optimum pH is changed C
• The catalytic activity is poisoned by a co-enzymes D

• Diastase A
• Lipase B
• Inverters C
• Zymase 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

It rate law of an equation is written asdx/dt=K[A][B] ?

• Reaction is independent of the concentration of A and B. A
• Product is decreasing with passage of time. B
• Reactant in increasing with passage of time. C
• Reactant is increasing with passage of time. D

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

• First order reaction A
• Second order reaction B
• Third order reaction C
• Zero order reaction 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 of reaction between two specific time intervals is called

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

• Rate is independent of concentration of water since it is in excess A
• Rate is independent of concentration of ester since it is in exces B
• Rate depends upon the concentration of acid catalyst added C
• Rate = k[CH₃COOC₂H₅]^1/2[H₂O]^1/2 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

If initial concentration of the reactants and half life period of the reaction is known, then we can determine

• Average rate of reaction A
• Order of reaction B
• Rate constant k C
• Instantaneous rate 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

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

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

Platinum is poisoned by

• Arsenic A
• Silver B
• Argon C
• Zinc 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

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

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

• 3 A
• 2 B
• 1 C
• 1 D

For a chemical reaction to take place the particles must have sufficient energy for the effective collisions, the energy is called

• Average energy A
• Activation energy B
• Potential energy C
• Collision energy D

By the use of catalysis the energy of activation is

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

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