Practice Pakistan's most useful MCQs for competitive exams

For the non-catalytic reaction of particles with surrounding fluid, the time needed to achieve the same fractional conversion for particles of different but unchanging sizes is proportional to the square of particle diameter, when the _______________ is the controlling resistance?

• (A)  Film diffusion
• (B)  Diffusion through ash layer
• (C)  Chemical reaction
• (D)  Either

Answer

Submitted By :Ali Uppal

A first order gaseous phase reaction is catalysed by a non-porous solid. The kinetic rate constant and the external mass transfer co-efficients are k and kg respectively. The effective rate constant (keff) is given by________________?

• (A)  keff = k + kg
• (B)  keff = (k+ kg)/2
• (C)  keff = (kkg)1/2
• (D)  1/keff = 1/k + 1/kg

Answer

Submitted By :Ali Uppal

Decomposition rate of a liquid ‘X’ which decomposes as per the reaction as shown in the bellow figure is given by________________?

• (A)  K1 . CX
• (B)  (K1 + K2 + K3) CX
• (C)  (K1 + K2) CX
• (D)  (K2 + K3) CX

Answer

Submitted By :Ali Uppal

The sequence in which three CSTR’s of volumes 5, 10 and 15 m3 will be connected in series to obtain the maximum production in a second order irreversible reaction is ____________________?

• (A)  15, 10, 5
• (B)  5, 10, 15
• (C)  10, 5, 15
• (D)  10, 15, 5

Answer

Submitted By :Ali Uppal

Given, 3H2 + CO = CH4 + H2O, KP = 101.84 and, 4H2 + CO2 = CH4 + 2H2O, KP = 101.17 the KP for the reaction CO + H2O = CO2 + H2 is __________________?

• (A)  103.01
• (B)  10-0.67
• (C)  10-3.01
• (D)  100.67

Answer

Submitted By :Ali Uppal

______________ catalytic reaction is involved in the thermal cracking of gas oil ?

• (A)  Homogeneous
• (B)  Non-Homogeneous
• (C)  Heterogeneous
• (D)  Non-Heterogeneous

Answer

Submitted By :Ali Uppal

The residence time distribution of an ideal CSTR is _____________________?

• (A)  (1/η) exp (-t/η)
• (B)  η exp (-t/η)
• (C)  exp (-t/η)
• (D)  (1/η) (-t/η)

Answer

Submitted By :Ali Uppal

Which of the following is not a unit of reaction rate ?

• (A)  Moles for med/(surface of catalyst) (time)
• (B)  Moles formed/volume of reactor) (time)
• (C)  Mole formed/volume of catalyst) (time)
• (D)  None of these

Answer

Submitted By :Ali Uppal

Rate of a chemical reaction is independent of the concentration of the reactants for a _________________ reaction?

• (A)  Zero order
• (B)  Third order
• (C)  Consecutive
• (D)  None of these

Answer

Submitted By :Ali Uppal

A batch reactor suffers from following disadvantage ?

• (A)  Poor product quality control
• (B)  High labour and handling cost
• (C)  High shutdown time requirement for emptying, cleaning and refilling
• (D)  All

Answer

Submitted By :Ali Uppal