Chemical Reaction Engineering GATE-1994
Q 1: To maximize the formation of R in the simultaneous reactions
A+B\rightarrow R\;\;r_R=2C_A^{0.5}C_B^2 A+B\rightarrow S\;\;r_S=1.5C_AC_Bwe should have
Fill in the Blanks Q 2, 3 & 4:
Q 2: The Arrhenius equation for the temperature dependency of the reaction rate constant is ____________.
Q 3: For a given conversion and a first-order reaction, the volume required for a mixed reactor is __________ than that for a plug flow reactor.
Q 4: The rate of reaction is defined as _______.
State with reasons whether the statement is true or false Q 5, 6, 7 & 8:
Q 5: If the rate of the irreversible reaction A + B → 2C is kCACB, then the reaction is always elementary.
Q 6: Two mixed reactors of unequal size are available for producing a specified product, formed by a homogeneous second-order reaction. To achieve maximum production rate, the smaller reactor should be placed in series before the larger reactor.
Q 7: For the same conversion, the holding time required in a batch reactor is always equal to space-time required in a plug flow reactor.
Q 8: The mechanism for the decomposition of CH3 CHO into CH4 and CO in the presence of I2 is
CH_3CHO+I_2\rightarrow CH_3+HI+CO;\;\;slow CH_3I+HI\rightarrow CH_4+I_2;\;\;\;fastThen, the rate of disappearance of CH3CHO is equal to C_{CH_3I}C_{HI} and HI acts as a catalyst
Q 9: Match the items in the left column with the appropriate items in the right column
| Group-I | Group-II |
| I: A → B → C | A: rate of reaction of A shows maximum with time |
| II: A +B → 2B + C | B: CB shows a maximum with time |
| C: CC shows a maximum with time | |
| D: CB continuously decreases with time |
Q 10: In a batch reactor an irreversible first-order reaction A → R takes place. The reaction rate constant (k) = 0.2 sec-1, and the initial concentration of A (CA0) = 0.1 mol/m3. Find the conversion of the reactant after 2 seconds.
Q 11: The Thiele modulus for a first-order isothermal reaction for a flat plate geometry catalyst is found to be 2. Calculate the catalyst effectiveness factor.
Q 12: A gaseous reactant diffuses through a gas film and reacts on the surface of a non-porous spherical catalyst particle. The rate of surface reaction is k1CS, where CS is the reactant concentration on the catalyst surface. The reaction rate constant (K1) = 0.83×10-4 m/s and the gas film mass transfer coefficient (km) = 1.66×10-4 m/s. Derive the reaction rate expression in terms of bulk gas phase concentration (CG).
Q 13: 50 % conversion is obtained in a CSTR for a homogeneous, isothermal, liquid phase, irreversible second-order reaction. What is the conversion if the reactor volume is five times the original-all else remaining unchanged?
Q 14: A homogeneous gas phase decomposition reaction 4A → B + 7S takes place in an isothermal plug flow reactor. The reaction rate is, -rA = k1CA with k1 = 0.17 s-1; feed concentration of A (CA0) = 0.1 mol/m3 Feed Flow rate (FA0) = 0.17 mol/s. Determine the size of the reactor in order to achieve 50 % conversion.