For the liquid phase zero order reaction
A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of
0.1 min. What will be the conversion for a PFR with a space velocity of 0.2 min-1.
Assume that all the other operating conditions are same for CSTR and PFR.
(A)
0.15
(B)
0.25
(C)
0.35
(D)
0.45
GATE
1999
Answer: (A)
Consider the nth order irreversible
liquid phase reaction A → B. Which one of the following plots involving
half-life of the reaction (t1/2) and the initial reactant
concentration (CA0) gives a straight line plot?
(A)
CA0 vs t1/2
(B)
lnCA0 vs t1/2
(C)
CA0 vs lnt1/2
(D)
lnCA0 vs lnt1/2
GATE
1999
Answer: (D)
At a given value of E/R (ratio of
activation energy and gas constant), the ratio of the rate constant at 500 K
and 400 K is 2 if Arrhenius law is used. What will be this ratio if transition
state theory is used with the same value of E/R?
(A)
1.6
(B)
2
(C)
2.24
(D)
2.5
GATE 1999
Answer: (D)
For the reaction A + B → 2B + C
(A)
rA = rB
(B)
rA = -rB
(C)
rA = 2rB
(D)
rA = rB/2
GATE
1999
Answer: (B)
Overall order of reaction for which the
rate constant has units of (mol/lit)-3/2 is
(A)
-3/2
(B)
½
(C)
3/2
(D)
5/2
GATE
1999
Answer: (D)
For the reaction P + 2Q → 3R, molar rate
of consumption of P is
(A)
double of that of Q
(B)
same as that of Q
(C)
half of that of Q
(D)
2/3 of that of Q
GATE
1998
Answer: (C)
Molecularity of an elementary reaction
P + Q → R + S is
(A)
1
(B)
2
(C)
3
(D)
4
GATE
1998
Answer: (B)
For a given duty and for all positive
reaction orders, the size of a mixed reactor is
(A)
Smaller than that of a plug flow reactor
(B)
Same as that of a plug flow reactor
(C)
Larger than that of a plug flow reactor
(D)
None of the above
GATE
1998
Answer: (C)
A reversible liquid phase endothermic
reactions is to be carried out in a plug flow reactor. For minimum reactor
volume it should be operated such that the temperature along the length
(A)
Decreases
(B)
Increases
(C)
Is at the highest allowable temperature
(D)
First increases and then decreases
GATE
1997
Answer: (C)
The
gas phase reaction 2A → B is carried out in an isothermal plug flow reactor.
The feed consists of 80 mole% A and 20 mole% inerts. If the conversion of A at
the reactor exit is 50%, then CA/CA0 at the outlet of the
reactor is
(A)
2/3
(B)
5/8
(C)
1/3
(D)
3/8
GATE
1997
Answer: (B)
For first order isothermal chemical
reaction in a porous catalyst, the effectiveness factor is 0.3. The
effectiveness factor will increase if the
(A) Catalyst
size is reduced or the catalyst diffusivity is reduced
(B)
Catalyst size is reduced or the catalyst
diffusivity is increased
(C)
Catalyst size is increased or the
catalyst diffusivity is reduced
(D) Catalyst
size is increased or the catalyst diffusivity is increased
GATE
1997
Answer: (B)
From Collision theory, the reaction rate
constant is proportional to
GATE
1996
Answer: (D)
The Kundsen diffusivity is dependent on
(A)
The molecular velocity only
(B)
The pore radius of the catalysis only
(C)
The molecular mean free path only
(D)
The molecular velocity and pore radius
of the catalysts
GATE
1996
Answer: (D)
For a first order chemical reaction in a
porous catalyst, the Thiele modulus is 10. The effectiveness factor is
approximately equal to
(A)
1
(B)
0.5
(C)
0.1
(D)
0
GATE
1996
Answer: (C)
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
GATE
1996
Answer: (C)
The energy balance equation over a tubular reactor
under transient conditions is
(A)
An ordinary non-linear differential
equation
(B)
An algebraic equation
(C)
A linear partial differential equation
(D)
A non-linear partial differential
equation
GATE
1996
Answer: (D)
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.XA/V
(D)
–dCA/dt
GATE
1996
Answer: (C)
For a tubular reactor with space time τ
and residence time θ, the following statement holds
(A)
τ and θ are always equal
(B)
τ = θ when the fluid density changes in
the reactor
(C)
τ = θ for an isothermal tubular reactor
in which the density of the process fluid is constant
(D)
τ = θ for a non-isothermal reactor
GATE
1996
Answer: (C)
For an isothermal variable volume batch
reactor, the following reaction is applicable for a first order irreversible
reaction.
GATE
1996
Answer: (C)
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