Practice Test: Question Set - 24
1. The half life period of a first order reaction is given by (where, K = rate constant.)
- (A) 1.5 K
- (B) 2.5 K
- (C) 0.693/K
- (D) 6.93 K
2. In a/an __________ vessel, the fluid enters and leaves following plug flow.
- (A) Open
- (B) Closed
- (C) Open-closed
- (D) Close-opened
3. The reason why a catalyst increases the rate of reaction is that, it
- (A) Decreases the energy barrier for reaction
- (B) Increases the activation energy
- (C) Decreases the molecular collision diameter
- (D) None of these
4. 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
5. 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
6. The eddy diffusivity for a liquid in plug flow must be
- (A) 1
- (B) 0
- (C) ∞
- (D) Between 0 and 1
7. A catalyst
- (A) Initiates a reaction
- (B) Lowers the activation energy of reacting molecules
- (C) Is capable of reacting with any one of the reactants
- (D) Cannot be recovered chemically unchanged at the end of a chemical
reaction
8. Reaction of benzene with chlorine gas to produce tri-chlorobenzene exemplifies a/an __________ reaction.
- (A) Elementary
- (B) Parallel
- (C) Consecutive
- (D) None of these
9. The rate controlling step for the heterogeneous irreversible catalytic reaction A(g) + B(g) → C(g) is the surface reaction of absorbed A with absorbed B to give adsorbed C. The rate expression for this reaction can then be written as (where, KA, KB and KC are the equilibrium constants and is the rate constant of the rate controlling step.)
- (A) k KA pApB
/ (1 + KApA
+ KBpB)
- (B) k KAKB
pApB / (1 + KApA + KBpB)
- (C) k KAKB
pApB / (1 + KApA + KBpB + KCpC)
- (D) k KAKB
pApB / (1 + KApA + KBpB + KCpC)2
10. 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
11. Reaction rate equation for the bellow figure reaction, If S at is present in large excess, what is the order of this reaction?
- (A) Zero
- (B) One
- (C) Two
- (D) Three
12. 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
13. In the gaseous phase ammonia formation reaction (N2 + 3H2 ⇌ 2NH3), the value of the equilibrium constant depends on the
- (A) Total pressure of the system
- (B) Volume of the reactor
- (C) Temperature
- (D) Initial concentration of N2 and H2
14. 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 (a) or (b), depends on the type of reaction
15. For a heterogeneous catalytic reaction
- (A) Free energy of activation is lowered in the
presence of catalyst, which remains unchanged at the end of reaction
- (B) A relatively small amount of catalyst can cause the conversion of
large amount of reactants which does not mean that catalyst concentration is
important
- (C) The catalyst does not form an intermediate complex with the reactant
- (D) The surface of the catalyst does not play an important role during
reaction