The rate constant of a chemical reaction
increases by 100 times when the temperature is increased from 400 K to 500 K.
Assuming Transition state theory is valid, the value of E/R is
(A)
8987 K
(B)
9210 K
(C)
8764 K
(D)
8621 K
GATE
1995
Answer: (C)
The dimensions of rate constant for
reaction 3A → B are lit/(g.mol.min). Therefore the reaction order is
(A)
0
(B)
1
(C)
2
(D)
3
GATE 1995
Answer: (C)
A first order reaction A → B occurs in
an isothermal porous catalyst pellet of spherical shape. If the concentration
of A at the centre of the pellet is much less than that at the external
surface, the process is limited by
(A)
Diffusion within the pellet
(B)
Reaction
(C)
External mass transfer
(D)
None of the above
GATE 1995
Answer: (A)
To maximize the formation of R in the
simultaneous reactions
We should have
(A)
Low CA, low CB
(B)
Low CA, high CB
(C)
High CA, low CB
(D)
High CA, high CB
GATE
1994
Answer: (B)
For the gaseous reaction 2A → B where
the feed consists of 50 mole% A and 50 mole% inerts, the expansion factor is
(A)
1
(B)
-0.5
(C)
-0.25
(D)
0
GATE
1994
Answer: (C)
The conversion of a reactant undergoing
a first order reaction at a time equal to three times the half life of the
reaction is
(A)
0.875
(B)
0.50
(C)
0.425
(D)
Not impossible to calculate because of
insufficient data
GATE 1992
Answer: (A)
A gaseous reaction A → 2B + C takes
place isothermally in a constant pressure reactor. Starting with a gaseous
mixture containing 50% A (rest inerts), the ratio of final to initial volume is
found to be 1.6. the percentage conversion of A is
(A)
30
(B)
50
(C)
60
(D)
74
GATE 1992
Answer: (C)
The unit of frequency factor in
Arrhenius equation
(A)
Are the same as those of the rate
constant
(B)
Depend on the order of the reaction
(C)
Depend on the temperature, pressure, etc
of the reaction
(D)
Are cycles per unit time
GATE 1992
Answer: (A)
Thiele modulus is defined as
(A)
D/K
(B)
K/D
(C)
L(K/D)0.5
(D)
LK/D
GATE
1991
Answer: (C)
The reaction between A and B produces
the desired product R as well as the unwanted product S. what level of reactant
concentration (high, medium, low) should we use for the following reaction
scheme in order to maximize the conversion of A to R.
Reaction scheme:
(A)
Low CA, low CB
(B)
High CB, any CA
(C)
High CA, low CB
(D)
High CA, any CB
GATE
1991
Answer: (B)
The rate of a liquid phase reaction of
the type A + B → P is found to be independent of concentration of A and B and
equal to 1 kmol/m3.min at 300 K. Find the conversion in a mixed flow
reactor having volume equal to 2 m3 with feed concentration of A and
b equal to 5 kmol/m3, feed flow rate equal to 1 m3/min
and the reactor temperature equal to 300 K.
(A) 0.4
(B)
0.5
(C)
0.6
(D) 0.7
GATE 1991
Answer: (A)
For an elementary reaction A + B →
products, the reaction rate at 500 K is ten times that at 400 K. Calculate the
activation energy for this reaction
(A)
38.29 KJ/g.mol
(B)
42.25 KJ/g.mol
(C)
46.25 KJ/g.mol
(D)
48.35 KJ/g.mol
GATE 1990
Answer: (A)
What is the exit conversion of reactant
A for a zero order reaction taking place in a CSTR with the following data
(rate constant = 1 mol/min.lit, feed concentration = 1 mole/lit, feed flow rate
= 0.5 lit/min and reactor volume = 1 lit)
(A)
50%
(B)
75%
(C)
100%
(D)
200%
GATE 1990
Answer: (D)
An exothermic gas phase reaction
proceeds according to the equation 3A + 2D 
2R. The equilibrium conversion for this
reaction
(A)
Increases with increase in temperature
(B)
Decreases on dilution with an inert gas
(C)
Decreases with an increase in pressure
(D)
Is unbaffled by the presence of a
catalyst
GATE
1990
Answer: (D)
In a homogeneous gas phase reaction A +
2B → R + S. What is the relationship between rA and rB?
(A)
2rA = rB
(B)
rA = 2rB
(C)
rA = rB
(D)
none of these
GATE
1990
Answer: (A)
For the following reaction, the rate
constant at 373 K is 0.5 per min 0.5 A + B → C. The overall order of reaction
is
(A)
0.5
(B)
1.0
(C)
1.5
(D)
0
GATE
1989
Answer: (B)
From the stoichiometry, one can say that
the following reaction is non-elementary
N2 + 3H2 → 2NH3
The reason is
(A)
No elementary reaction has an order
greater than 2
(B)
The order of the forward reaction is not
the same as that of the backward reaction
(C)
The reaction takes place in gas phase
only
(D)
None of these
GATE
1989
Answer: (A)
In transition state theory the rate of
the reaction is derived by assuming that the activated complex in equilibrium
with
(A)
The products
(B)
The reactants
(C)
Both reactants and products
(D)
None of the above
GATE
1988
Answer: (B)
Liquid A decomposes by first order
kinetics in an isothermal batch reactor. 50% of A is converted in 300 seconds.
The time required for a conversion of 75% is
(A)
300 × 0.75/0.25 sec
(B)
300 ln 1 sec
(C)
300 ln(0.5/0.25) sec
(D)
300 {(ln0.25)/(ln0.5)}
GATE
1988
Answer: (D)
The reaction A → B occurs in an
isothermal catalyst pellet under steady state conditions. If the diffusion of A
into the pellet is the rate controlling steps, the rate of diffusion of A is
(A)
Faster than the rate of reaction
(B)
Equal to the rate of reaction
(C)
Slower than the rate of reaction
(D)
May be faster or slower depending on the
kinetics
GATE
1988
Answer: (C)
