Practice Pakistan's most useful MCQs for competitive exams

Chemical reaction rate of a component depends upon the______________________?

• (A)  Composition of the component only
• (B)  Temperature of the system
• (C)  Pressure of the system
• (D)  All

Answer

Submitted By :Ali Uppal

If helium is introduced in a reactor containing O2, SO2 and SO3 at equilibrium, so that total pressure increases while volume and temperature remains constant. In this case the dissociation of SO3 (as per Le Chatelier’s principle)?

• (A)  Decreases
• (B)  Increases
• (C)  Remains unaltered
• (D)  Changes unpredictably

Answer

Submitted By :Ali Uppal

For a first order reaction carried out in a plug flow reactor, the space time is__________________?

• (A)  (1/k) ln C0/C
• (B)  (1/k) ln C/C0
• (C)  k ln C0/C
• (D)  k ln C/C0

Answer

Submitted By :Ali Uppal

If the pore diffusion controls in a catalytic reaction, the apparent activation energy Ea is equal to___________________?

• (A)  The intrinsic activation energy E
• (B)  (E + ED) where ED is activation due to diffusion
• (C)  (E + ED)/2
• (D)  ED/2

Answer

Submitted By :Ali Uppal

When an exothermic reversible reaction is conducted adiabatically, the rate of reaction____________________?

• (A)  Continuously increases
• (B)  Continuously decreases
• (C)  Passes through a maximum
• (D)  Passes through a minimum

Answer

Submitted By :Ali Uppal

Reactions with high activation energy are_____________________?

• (A)  Very temperature sensitive
• (B)  Temperature insensitive
• (C)  Always irreversible
• (D)  Always reversible

Answer

Submitted By :Ali Uppal

The conversion in a mixed reactor/accomplishing a reaction A → 3R is 50% when gaseous reactant ‘A’ is introduced at the rate of 1 litre/second and the leaving flow rate is 2 litres/second. The holding time for this operation is _______________ second?

• (A)  0.5
• (B)  1
• (C)  2
• (D)  3

Answer

Submitted By :Ali Uppal

A Catalyst ____________________?

• (A)  Increases the equilibrium concentration of the product
• (B)  Changes the equilibrium constant of the reaction
• (C)  Shortens the time to reach the equilibrium
• (D)  None of these

Answer

Submitted By :Ali Uppal

For a mixed flow reactor operating at steady state, the rate of reaction is given by______________?

• (A)  (FA0/V) – (dCA/dt)
• (B)  (FA0/V) + (dCA/dt)
• (C)  (FA0/V) XA
• (D)  -(dCA/dt)

Answer

Submitted By :Ali Uppal

With increase in the order of reaction (for all positive reaction orders), the ratio of the volume of mixed reactor to the volume of plug flow reactor (for identical feed composition, flow rate and conversion)?

• (A)  Increases
• (B)  Decreases
• (C)  Remain same
• (D)  Increases linearly

Answer

Submitted By :Ali Uppal