A. Lessens its selectivity
B. May be useful for suppressing undesirable side reactions
C. Is added in small quantity during the catalyst manufacture itself
D. All A., B. and C.
Correct Answer: D. All A., B. and C. ✔
Last Updated: February 20, 2019
Related MCQs
- Calcination reaction of limestone (CaCO3 → CaO + CO2) goes to completion in the rotary kiln, because__________?
- Which of the following curves shows the effect of temperature on the extent of gas-solid adsorption at a given pressure ?
- Promoter is added to the catalyst to improve its__________?
- A batch reactor is characterised by __________?
- Concentration of the limiting reactant (with initial concentration of a moles/litre) after time t is (a-x). Then ‘t’ for a first order reaction is given by__________?
- What is the maximum possible value of FR(mole/sec.) ?
- A second order reaction of the form A + B → C is called a pseudo-first order reaction, when__________?
- Pure A in gas phase enters a reactor 50% of this A is converted to B through the reaction, A → 3B. Mole fraction of A in the exit stream is__________?
- A chemical reaction occurs when the energy of the reacting molecules is __________ the activation energy of the reaction?
- 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?
- A first order gaseous phase reaction is catalysed by a non-porous solid. The kinetic rate constant and the external mass transfer co-efficients are k and kg respectively. The effective rate constant (keff) is given by__________?
- Decomposition rate of a liquid ‘X’ which decomposes as per the reaction as shown in the bellow figure is given by__________?
- The sequence in which three CSTR’s of volumes 5, 10 and 15 m3 will be connected in series to obtain the maximum production in a second order irreversible reaction is __________?
- Given, 3H2 + CO = CH4 + H2O, KP = 101.84 and, 4H2 + CO2 = CH4 + 2H2O, KP = 101.17 the KP for the reaction CO + H2O = CO2 + H2 is __________?
- Which of the following is not a dimension-less group used in catalysis? (Where, D = dispersion co-efficient, cm2/sec.D1 = diffusion co-efficient; cm2/sec L = length of the reactor, cm t = time, sec, v = volumetric flow rate, cm3/sec. V = volume, cm3.) ?
- The conversion XA and residence time data are collected for zero order liquid phase reaction in a stirred tank reactor. Which of the following will be a straight line ?
- For the reaction as shown in the bellow figure, the rate of formation of Z is 0.2 gm mole/litre.hr. What is the rate of disappearance of X in gm mole/litre.hr ?
- The ‘E’ curve for a non-ideal reactor defines the fraction of fluid having age between t and t + dt __________?
- Molecularity of an elementary reaction, P + Q → R + S is __________?
- The exit age distribution of a fluid leaving a vessel (denoted by E) is used to study the extent of non-ideal flow in the vessel. The value of ∫∞ 0 E.dt is__________?
- Effectiveness factor E. of a catalyst pellet is defined as, E = (actual rate within pore of the catalyst)/(rate if not snowed by pore diffusion), Effectiveness factor for a first order reaction is given by (where, T = Thiele modulus) __________?
- Photo-chemical reactions occur in presence of __________?
- The conversion of a reactant, undergoing a first order reaction, at a time equal to three times the half life of the reaction is ?
- The heat of reaction__________?
- Space velocity__________?
- A chemical reaction occurs, when the energy of the reacting molecules is __________ the activation energy of reaction?
- For a __________ order reaction, the units of rate constant and rate of reaction are the same ?
- The conversion for a first order liquid phase reaction. A → B in a CSTR is 50%. If another CSTR of the same volume is connected in series, then the % conversion at the exit of the second reactor will be__________?
- For the same residence time, which one will give the maximum conversion ?
- 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) ?
- ‘Unreacted core model’ represents the reaction involving __________?
- The value of Steric factor ‘P’ in the equation k = PZeE/RT usually ranges from __________?
- Half life period of a first order irreversible reaction A → B is __________?
- A stirred tank reactor compared to tubular-flow reactor provides__________?
- The rate of an autocatalytic reaction as shown in the bellow figure, is given by – rA = k . CA . CB. In this case, the__________?
- Fluid flow in a real packed bed can be approximated as __________ model?
- The first order gas phase reaction as shown in the bellow figure is conducted isothermally in batch mode. The rate of change of conversion with time is given by__________?
- Three plug flow reactors (PFR’s) of 4, 5 & 6 m3 volumes are arranged in two branches as shown below in the figure. If the total feed rate is 300 tons/hr, then for the same conversion in each branch, the feed rate through branch II should be __________ tons/hr ?
- An irreversible first order reaction is being carried out in a CSTR and PFR of same volume. The liquid flow rates are same. The relative conversion will__________?
- For an ideal mixed flow reactor (CSTR), the exit age distribution E(t) is given by __________?
- In case of a P.F.R., there__________?
- The rate of the reaction, X → Y, quadruples when the concentration of ‘X’ is doubled. The rate expression for the reaction is, r = K Cx n, the value of ‘n’ in this case will be__________?
- The rate of a homogeneous reaction is a function of__________?
- For series reaction, the relative yield__________?
- In autocatalytic reactions ?
- The dispersion number of perfect mixed flow is__________?
- Which of the following does not produce a change in the value of rate constant of a reaction ?
- 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 __________?
- The energy of activation of a chemical reaction ?
- If pore diffusion is the controlling step in a solid catalysed reaction, the catalyst__________?
- With the same reaction time, initial concentration and feed rate, the reaction 2A → B is carried out separately in CSTR and P.F. reactor of equal volumes. The conversion will be__________?