Practice Pakistan's most useful MCQs for competitive exams

The rate of the heterogeneous catalytic reaction A(g) + B(g) → C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction is_______________?

• (A)  Absorption of A
• (B)  Surface reaction between absorbed A and absorbed B
• (C)  Surface reaction between absorbed A and B in the gas phase
• (D)  Surface reaction between A in the gas phase and absorbed B

Answer

Submitted By :Ali Uppal

The rate equation for the reaction represented by as shown in the bellow figure, is given by – rx = K1 . Cx/(1 + K2 Cx). At high value of Cx (i.e.., K2Cx > > 1), the order of the reaction and the rate constant are respectively___________________?

• (A)  Zero order & K1/K2
• (B)  Zero order & K1
• (C)  First order & K1
• (D)  First order & K1/K2

Answer

Submitted By :Ali Uppal

The temperature dependence of reaction rate constant (K) by Arrhenius law is given by_______________?

• (A)  K α e-E/RT
• (B)  K α eE/RT
• (C)  K α T . e-E/RT
• (D)  K α √T . e-E/RT

Answer

Submitted By :Ali Uppal

In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for________________?

• (A)  Fast reactions in catalyst of small pore diameter
• (B)  Fast reaction in catalyst of large pore diameter
• (C)  Slow reactions in catalyst of small pore diameter
• (D)  Slow reactions in catalyst of large pore diameter

Answer

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Half-life period for a first order reaction is _____________ the initial concentration of the reactant?

• (A)  Directly proportional to
• (B)  Inversely proportional to
• (C)  Independent of
• (D)  None of these

Answer

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Recycling back of outlet stream to the reactor from an ideal CSTR carrying out a first order liquid phase reaction will result in ______________ in conversion?

• (A)  Decrease
• (B)  Increase
• (C)  No change
• (D)  Either

Answer

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In case of a _____________ reactor, the composition in the reactor and at the exit of the reactor is the same ?

• (A)  Semi-batch
• (B)  Tubular
• (C)  Batch
• (D)  Back-mix

Answer

Submitted By :Ali Uppal

Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the ___________________?

• (A)  Activation energy
• (B)  Equilibrium constant
• (C)  Heat of reaction
• (D)  None of these

Answer

Submitted By :Ali Uppal

Reaction of benzene with chlorine gas to produce tri-chlorobenzene exemplifies a/an ______________ reaction?

• (A)  Elementary
• (B)  Parallel
• (C)  Consecutive
• (D)  None of these

Answer

Submitted By :Ali Uppal

In which of the following gaseous phase reversible reactions, the product yield cannot be increased by the application of high pressure ?

• (A)  N2 + O2 ⇌ 2NO
• (B)  PCl3 + Cl2 ⇌ PCl5
• (C)  N + 3H2 ⇌ 2NH3
• (D)  2SO2 + O2 ⇌ 2SO3

Answer

Submitted By :Ali Uppal