3. For the non catalytic reaction of particles with surrounding fluid, the same needed to achive the same fractional conversion for particles of different unchanging sizes is proportional to the particle diameter, when the __________ is the controlling resistance.
4. For the non-catalytic reaction of particles with surrounding fluid, the time needed to achieve the same fractional conversion for particles of different but unchanging sizes is proportional to the square of particle diameter, when the __________ is the controlling resistance.
10. 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
14. Time required for 50% decomposition of a liquid in an isothermal batch reactor following first order kinetics is 2 minutes. The time required for 75% decomposition will be about __________ minutes.
17. A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 kmole/m³ and volumetric flow rate 1m³ /h requires a mixed flow reactor of volume V to bring down the pollutant level to 0.5 kmole/m³ . The inlet concentration of the pollutant is now doubled and the volumetric flow rate is tripled. If the pollutant level is to be brought down to the same level of 0.5 kmole/m³ , the volume of the mixed flow reactor should be increased by a factor of
34. A CSTR is to be designed in which an exothermic liquid phase first order reaction of the type, A → R, is taking place. The reactor is to be provided with a jacket in which coolant is flowing. Following data is given: CA0= 5 kmole/m³ ; XA = 0.5; Feed temperature = reactor temperature = 40°C. Rate constant at 40°C = 1 min⁻¹ ; (ΔH) = – 40kJ/mole; ρ = 1000kg/m³ CP = 4 J/gm.°C ; q = 10⁻³ m³/min (ρ and CP are same for the reactant and product streams). The amount of heat to be removed is
39. For the chemical reaction P → Q, it is found that the rate of reaction doubles as the concentration of ‘P’ is doubled. If the reaction rate is proportional to Cpn, then what is the value of ‘n’ for this chemical reaction
67. In a first order reaction, the time required to reduce the concentration of reactant from 1 mole/litre to 0.5 mole/litre will be __________ that required to reduce it from 10 moles/litre to 5 moles/litre in the same volume.
80. In the hydrodealkylation of toluene to benzene, the following reactions occur:C₇H₈ + H₂ → C₆H₆ + CH₄2C₆H₆ ⇋ C₁₂H₁₀ + H₂Toluene and hydrogen are fed to a reactor in a molar ratio 1:5.80% of the toluene gets converted and the selectivity of benzene(defined as moles of benzene formed/moles of toluene converted) is 90%. The fractional conversion of hydrogen is
91. The conversion in a mixed reactor/accomplishing a reaction A 3R is 50% when gaseous reactant ‘A’ is introduced at the rate of 1 litre/second and the leaving flow rate is 2 litres/second. The holding time for this operation is __________ second.
106. Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme ptyalin used for food digestion is present in
109. For a gaseous phase reaction, rate of reaction is equal to K. CA . CB. If the volume of the reactor is suddenly reduced to l/4th of its initial volume, then the rate of reaction compared to the original rate will be __________ times.
110. The rate of a gas phase reaction is given by K . CA . CB. If the volume of the reaction vessel is reduced to l/4th of its initial volume, then the reaction rate compared to the original rate will be __________ times.
118. The rate of the heterogenous catalytic reaction A(g) + B(g) ? C(g) is given by -rA = k.KA.pA.PB/(1 + KA.PA + Kc.pc), where KA and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction isA. absorption of A.
139. “A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true?A. Inner catalyst core of radius R/8 does not participate in reaction.”
143. The following gas phase reactions are carried out isothermally in a CSTR.A → 2R ; r₁ = K₁pA ;K₁ = 20mole/(sec.m³ bar)A → 3S ; r₂ = K₂ pA ;K₂ = 40mole/ (sec.m³ .bar)What is the maximum possible value of FR(mole/sec.) ?
146. The effectiveness factor for large value of Thiele modulus (L√(K/D1)) of a solid catalysed first order reaction is equal to (where, L = length of the reactor, cm, D1 = diffusion co-efficient, cm²/second)
158. 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
182. For identical flow rate, feed composition and for elementary first order reactions, ‘N’ equal sized mixed reactors in series with a total volume ‘V’ gives the same conversion as a single plug flow reactor of volume ‘V’ for constant density systems. This is true, when the value of ‘N’ is