Reaction Engineering (Set 1) Flashcards
Concepts necessary for reactor design, operation, and maintenance.
Which of the following will give maximum gas conversion?
Semi-fluidised bed reactor.
____ explains the mechanism of catalysis.
Activated complex theory
From among the following, choose one which is not an exothermic process.
Catalytic cracking
The fractional volume change of the system for the isothermal gas phase reaction, A 3B , between no conversion and complete conversion is
2
A catalyst
lowers the activation energy of reacting molecules.
What is the order of a chemical reaction, A + 2B (K)→ C, if the rate of formation of ‘C’, increases by a factor of 2.82 on doubling the concentration of ‘A’ and increases by a factor of 9 on trebling the concentration of ‘B’?
7/2
For high conversion in a highly exothermic solid catalysed reaction, use a ____ bed reactor.
fluidised bed reactor followed by a fixed
For every 10°C rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70°C, the rate of reaction increases ____ times.
16
The single parameter model proposed for describing non-ideal flow is the ____ model.
a. tank in series
b. dispersion
both (a) & (b)
A first order reaction requires two equal sized CSTR. The conversion is
more when they are connected in series.
In case of physical adsorption, the heat of adsorption is of the order of ____ kcal/kg.mole.
1000
The most unsuitable reactor for carrying out reactions in which high reactant concentration favours high yields is
backmix reactor
Pick out the wrong statement pertaining to space velocity of flow reactors.
a. The unit of space velocity is (time)-1 .
b. The space velocity of 3 hr-1 means that three reactor volumes of feed at specified conditions are being fed into the reactor every hour.
c. The space velocity of 3 hr-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor.
The space velocity of 3 hr-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor.
A reactor is generally termed as an autoclave, when it is a
high pressure batch reactor.
6 gm of carbon is burnt with an amount of air containing 18 gm oxygen. The product contains 16.5 gms CO2 and 2.8 gms CO besides other constituents. What is the degree of conversion on the basis of disappearance of limiting reactant ?
0.95
The rate constant of a chemical reaction decreases by decreasing the
temperature
Reaction rate equation for the reaction, https://www.indiabix.com/_files/images/chemical-engineering/chemical-reaction-engineering/448-153-1.png . If S at is present in large excess, what is the order of this reaction?
one
Rate of a gaseous phase reaction is given by, https://www.indiabix.com/_files/images/chemical-engineering/chemical-reaction-engineering/460-311-1.png . The unit of rate constant is
(atm)-1.(hr)-1
____ is the response curve for a step input signal from a reactor.
S-curve
If the catalyst pore size is small in comparison with the mean free path, collisions with the pore wall controls the process’. The diffusivity under this condition is called ‘Knudsen diffusivity’, which is affected by the
temperature
Which of the following is the most suitable for very high pressure gas phase reaction ?
Tubular flow reactor
The reaction between oxygen and organic material is a/an ____ reaction.
exothermic
With decrease in temperature, the equilibrium conversion of a reversible endother-mic reaction
decreases
In an exothermic chemical reaction, the reactants compared to the products have
more energy
For a reaction of the type, https://www.indiabix.com/_files/images/chemical-engineering/chemical-reaction-engineering/458-286-1.png , the rate of reaction (- rx) is given by
K1CV - K2CX
In a consecutive reaction system https://www.indiabix.com/_files/images/chemical-engineering/chemical-reaction-engineering/446-134-1.png when E1 is much greater than E2, the yield of B increases with the
increase of temperature.
A reversible liquid phase endothermic reaction 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
is at the highest allowable temperature throughout.
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
9210°K
A batch reactor is suitable for
liquid phase reactions.
For a heterogeneous catalytic reaction
free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction.
The increase in the rate of reaction with temperature is due to
decrease in activation energy.
A catalyst loses its activity due to
a. loss in surface area of the active component.
b. agglomeration of metal particles caused by thermal sintering of the solid surface.
c. covering of the catalytic active sites by a foregin substance.
all (a), (b) and (c).
N’ plug flow reactors in series with a total volume ‘V’ gives the same conversion as a single plug flow reactor of volume ‘V’ for ____ order reactions.
any
Specific rate constant for a second order reaction
a. is independent of temperature.
b. varies with temperature.
c. depends on the nature of the reactants.
both (b) and (c).
For the irreversible elementary reactions in parallel viz https://www.indiabix.com/_files/images/chemical-engineering/chemical-reaction-engineering/455-247-1.png , the rate of disappearance of ‘X’ is equal to
CA(K1+K2)
For an isothermal variable volume batch reactor, the following relation is applicable for a first order irreversible reaction.
CAo/(1+εAXA)(dXA/dt) = k
For a zero order chemical reaction, the
all (a), (b) and (c).
BET apparatus
a. measures the catalyst surface area directly.
b. operates at very high pressure.
c. is made entirely of stainless steel.
none of these.
Radioactive decay follows ____ order kinetics.
first
The excess energy of reactants in a chemical reaction required to dissociate into products is termed as the ____ energy.
activation