ECAT Pre Engineering Chemistry Chapter 11 MCQ Test With Answer

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

Rate of chemical reaction depends upon :

• The number of total collisions per second. A
• Number of molecules taking part in a chemical reaction. B
• Number of fruitful collisions per second C
• Number of fruitless collisions per second. 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

• Homogeneous A
• Heterogeneous B
• Isogeneous C
• None 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

______ are called biocatalysts

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

A catalyst is a substance which increase the rate of a chemical reaction, but remains unchanged at the end of reaction, nut remains unchanged at the end of reaction, because

• It increases the temperature A
• It increase the surface area B
• It increases the rate constant C
• It decrease the energy energy of activation D

It is common observation that rates of chemical reactions differ :

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

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

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

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

• Zero A
• 1 B
• 2 C
• 1.5 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

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 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

Which technique is used to determine the absorption of radiations?

• Dilatometer method

  A

• Optical rotation method

  B

• Spectrometry

  C

• Refractometric method

  D

The addition of a catalyst to a reaction changes the

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

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 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 chemical method used for determination of rate of reaction is

• Spectroscopic A
• Conductiometric B
• Refractometric C
• Titration 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 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

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

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

• 3 A
• 2 B
• 1 C
• 1 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

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

Platinum is poisoned by

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