Practice Pakistan's most useful MCQs for competitive exams

There is no correspondence between stoichiometric and the rate equation in case of a/an _____________ reaction?

• (A)  Elementary
• (B)  Multiple
• (C)  Autocatalytic
• (D)  Non-elementary

Answer

Submitted By :Ali Uppal

Specific rate constant for a second order reaction__________________?

• (A)  Is independent of temperature
• (B)  Varies with temperature
• (C)  Depends on the nature of the reactants
• (D)  Both

Answer

Submitted By :Ali Uppal

A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true?

• (A)  Inner catalyst core of radius R/8 does not participate in reaction
• (B)  Inner catalyst core of radius R/2 does not participate in reaction
• (C)  Inner catalyst core of radius 7R/8 does not participate in reaction
• (D)  Effectiveness factor for a zero order reaction cannot be 7/8 as it must always be 1

Answer

Submitted By :Ali Uppal

If the time required to complete a definite fraction of reaction varies inversely as the concentration of the reactants, then the order of reaction is________________?

• (A)  1
• (B)  2
• (C)  3
• (D)  4

Answer

Submitted By :Ali Uppal

Velocity of a reaction depends upon the_________________?

• (A)  Nature of the reactants
• (B)  Concentration of the reactants
• (C)  Temperature at which the reaction is carried
• (D)  All

Answer

Submitted By :Ali Uppal

From among the following, choose one which is not an exothermic process ?

• (A)  Methanol synthesis
• (B)  Catalytic cracking
• (C)  Ammonia synthesis
• (D)  Oxidation of sulphur

Answer

Submitted By :Ali Uppal

A batch adiabatic reactor at an initial temperature of 373°K is being used for the reaction, A → B. Assume the heat of reaction is – 1kJ/mole at 373°K and heat capacity of both A and B to be constant and equal to 50J/mole.K. The temperature rise after a conversion of 0.5 will be ____________?

• (A)  5°C
• (B)  10°C
• (C)  20°C
• (D)  100°C

Answer

Submitted By :Ali Uppal

The most unsuitable reactor for carrying out reactions in which high reactant concentration favours high yields is________________________?

• (A)  Backmix reactor
• (B)  Plug flow reactor
• (C)  Series of CSTR
• (D)  PFR in series

Answer

Submitted By :Ali Uppal

Pure ethanol vapor is fed to a reactor packed with alumina catalyst, at the rate of 100 kmole / hr. The reactor products comprise: ethylene: 95 kmole / hr, water vapour: 97.5 k mole / hr and diethyl ether: 2.5 kmole/hr. The reactions occuring can be represented by: C2H5OH → C2H4 + H2O 2C2H5OH → C2H5 – O – C2H5 + H2O The percent conversion of ethanol in the reactor is________________?

• (A)  100
• (B)  97.5
• (C)  95
• (D)  2.5

Answer

Submitted By :Ali Uppal

Vacuum maintained in the vacuum distillation tower of the crude distillation plant is about _______________ mm Hg (absolute)?

• (A)  5-10
• (B)  30-80
• (C)  150-250
• (D)  350-400

Answer

Submitted By :Ali Uppal