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MCQOPTIONS
This section includes 1443 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
The rate of a gas phase reaction is given by K . Cᴀ . Cʙ. If the volume of the reaction vessel is reduced to 1/4th of its initial volume, then the reaction rate compared to the original rate will be __________ times. |
| A. | 4 |
| B. | 16 |
| C. | 8 |
| D. | 2 |
| Answer» C. 8 | |
| 202. |
An isothermal aqueous phase reversible reaction, P ↔ R, is to be carried out in a mixed flow reactor. The reaction rate in k.mole/m³ .h is given by, r = 0.5Cₚ - 0.125Cʀ. A stream containing only P enters the reactor. The residence time required (in hours) for 40% conversion of P is |
| A. | 0.80 |
| B. | 1.33 |
| C. | 1.60 |
| D. | 2.67 |
| Answer» D. 2.67 | |
| 203. |
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. |
| A. | 0.5 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» B. 1 | |
| 204. |
What is the value of 'n' if the reaction rate of the chemical reaction A → B, is proportional to Cᴀⁿ and it is found that the reaction rate triples, when the concentration of 'A' is increased 9 times ? |
| A. | 1/2 |
| B. | 1/3 |
| C. | 1/9 |
| D. | 3 |
| Answer» B. 1/3 | |
| 205. |
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 |
| A. | 0.16 |
| B. | 0.144 |
| C. | 0.152 |
| D. | 0.136 |
| Answer» C. 0.152 | |
| 206. |
In the gaseous phase ammonia formation reaction (N₂ + 3H₂ ↔ 2NH₃), the value of the equilibrium constant depends on the |
| A. | total pressure of the system. |
| B. | volume of the reactor. |
| C. | temperature. |
| D. | initial concentration of N₂ and H₂. |
| Answer» D. initial concentration of N₂ and H₂. | |
| 207. |
The value of 'n' for a chemical reaction A → B, whose reaction rate is Cᴀⁿ, will be __________ if the rate of the reaction increases by a factor of 8, when the concentration of is doubled. |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» E. | |
| 208. |
The decomposition of A into B is represented by the exothermic reaction, A ↔ 2B. To achieve maximum decomposition, it is desirable to carry out the reaction. |
| A. | at high P and high T. |
| B. | at low P and high T. |
| C. | at low P and low T. |
| D. | at high P and low T. |
| Answer» D. at high P and low T. | |
| 209. |
For the liquid phase zero order irreversible reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1 min⁻¹ . What will be the conversion for a PFR with a space velocity of 0.2 min⁻¹ ? Assume that all the other operating conditions are the same for CSTR and PFR. |
| A. | 0.15 |
| B. | 0.30 |
| C. | 0.60 |
| D. | 0.90 |
| Answer» D. 0.90 | |
| 210. |
Find a mechanism that is consistent with the rate equation and reaction given below:2A + B → A₂B, ( - rᴀ) = k.Cᴀ.Cʙ |
| A. | A + B ↔ AB ; AB + A → A₂B |
| B. | A + B → AB;AB + A → A₂B |
| C. | A + A → AA;AA + B → A₂B |
| D. | A + A ↔ AA;AA + B → A₂B |
| Answer» E. | |
| 211. |
A pollutant P degrades according to first order kinetics. An aqueous stream containing P at 2 kmole/m³ and volumetric flow rate 1 m³/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 |
| A. | 7 |
| B. | 6 |
| C. | 3 |
| D. | 7/3 |
| Answer» B. 6 | |
| 212. |
Given, 3H₂ + CO = CH₄ + H₂O, Kₚ = 10^1.84 and, 4H₂ + CO₂ = CH₄ + 2H₂O, Kₚ = 10^1.17the Kₚ for the reaction CO + H₂O = CO₂ + H₂ is |
| A. | 10^3.01 |
| B. | 10^(-0.67) |
| C. | 10^(-3.01) |
| D. | 10^0.67 |
| Answer» E. | |
| 213. |
The fractional volume change of the system for the isothermal gas phase reaction, A → 3B , between no conversion and complete conversion is |
| A. | 0.5 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» D. 3 | |
| 214. |
Consider the 'n'th order irreversible liquid phase reaction A → B. Which one of the following plots involving half life of the reaction (t₁/₂) and the initial reactant concentration (Cᴀ₀) gives a straight line plot ? |
| A. | Cᴀ₀ Vs t₁/₂ |
| B. | ln Cᴀ₀ Vs t₁/₂ |
| C. | Cᴀ₀ Vs ln t₁/₂ |
| D. | ln Cᴀ₀ Vs ln t₁/₂ |
| Answer» D. ln Cᴀ₀ Vs ln t₁/₂ | |
| 215. |
During manufacture of H₂SO₄, the oxidation of SO₂ to SO₃ by oxygen is an en-dothermic reaction. The yield of SO₃ will be maximised, if the |
| A. | temperature is increased. |
| B. | pressure is reduced. |
| C. | temperature is increased and pressure is reduced. |
| D. | temperature is reduced and pressure is increased. |
| Answer» E. | |
| 216. |
For reactions in parallel viz A → P (desired product) and A → Q (unwanted product), if the order of the desired reaction is higher than that of the undesired reaction, a |
| A. | batch reactor is preferred over a single CSTR for high yield. |
| B. | tubular reactor is preferred over a single CSTR for high yield. |
| C. | both (a) and (b). |
| D. | single CSTR is the most suitable. |
| Answer» D. single CSTR is the most suitable. | |
| 217. |
In the reversible reaction of the type, A + B ↔ AB, in general |
| A. | both forward and backward reactions will be exothermic. |
| B. | neither of the reactions will be en-dothermic. |
| C. | the combination reaction will be exothermic, while the dissociation reaction will be endothermic. |
| D. | the combination reaction will be endothermic, while the dissociation reaction will be exothermic. |
| Answer» D. the combination reaction will be endothermic, while the dissociation reaction will be exothermic. | |
| 218. |
In which of the following reactions, the equilibrium will shift to the right, if the total pressure is increased? |
| A. | H₂ + Cl₂ ↔ 2HCl |
| B. | N₂ + O₂ ↔ 2NO |
| C. | N₂O₄ ↔ 2NO₂ |
| D. | H₂ + I₂ ↔ 2HI |
| Answer» C. N₂O₄ ↔ 2NO₂ | |
| 219. |
A first order irreversible reaction, A → B is carried out separately in a constant volume as well as in a variable volume reactor for a particular period. It signifies that __________ in the two reactors. |
| A. | both conversion as well as concentration are same |
| B. | conversion in both will be the same but concentrations will be different |
| C. | both the conversion as well as concentrations will be different |
| D. | none of these. |
| Answer» C. both the conversion as well as concentrations will be different | |
| 220. |
The irreversible reaction, X → Y, is the special case of the reversible reaction, X ↔ Y, in which the |
| A. | equilibrium constant is infinite. |
| B. | fractional conversion of 'A' at equilibrium is unity. |
| C. | concentration of 'A' at equilibrium is zero. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 221. |
Half life period of a chemical reaction is proportional to Cᴀ₀⁻¹ , if the reaction is of __________ order. |
| A. | first |
| B. | zero |
| C. | second |
| D. | third |
| Answer» D. third | |
| 222. |
The effect of increasing pressure on the gaseous equilibrium of the reaction 2X+3Y ↔ 3X+2Y indicates that |
| A. | pressure has no effect. |
| B. | backward reaction is favoured. |
| C. | forward reaction is favoured. |
| D. | none of these. |
| Answer» B. backward reaction is favoured. | |
| 223. |
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 |
| A. | higher in P.F. reactor |
| B. | higher in CSTR |
| C. | same in both the reactors |
| D. | data insufficient; can't be predicted |
| Answer» B. higher in CSTR | |
| 224. |
The rate of the reaction, X → Y, quadruples when the concentration of 'X' is doubled. The rate expression for the reaction is, r = K Cₓⁿ, the value of 'n' in this case will be |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» D. 3 | |
| 225. |
The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m³ is fed to the reactor at the rate of 0.01 m³ /s and at a temperature of 500 K. If the exit conversion is 20%, then the exit temperature (in k) is(Data: Heat of reaction at 298 K = - 50000 kJ/ kmole of A reacted Heat capacities CPA = CPB = 100 kJ/kmole. K (may be assumed to be independent of temperature)) |
| A. | 400 |
| B. | 500 |
| C. | 600 |
| D. | 1000 |
| Answer» D. 1000 | |
| 226. |
Pure ethanol vapor is fed to a reactor packed with alumina catalyst, at the rate of 100 kmole / hr. The reactor products comprise: ethylene :95 kmole / hr, water vapour: 97.5 k mole / hr and diethyl ether :2.5 kmole/hr. The reactions occuring can be represented by:C₂H₅OH → C₂H₄ + H₂O2C₂H₅OH → C₂H₅ - O - C₂H₅ + H₂OThe percent conversion of ethanol in the reactor is |
| A. | 100 |
| B. | 97.5 |
| C. | 95 |
| D. | 2.5 |
| Answer» B. 97.5 | |
| 227. |
The rate of the heterogenous catalytic reaction A(g) + B(g) → C(g) is given by -rᴀ = k.Kᴀ.pᴀ.Pʙ/(1 + Kᴀ.Pᴀ + Kc.pc), where Kᴀ and Kc are the adsorption equilibrium constants. The rate controlling step for this reaction is |
| A. | absorption of A. |
| B. | surface reaction between absorbed A and absorbed B. |
| C. | surface reaction between absorbed A and B in the gas phase. |
| D. | surface reaction between A in the gas phase and absorbed B. |
| Answer» D. surface reaction between A in the gas phase and absorbed B. | |
| 228. |
A pulse tracer is introduced in an ideal CSTR (with a mean residence time τ) at time, t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be |
| A. | 2τ |
| B. | 0.5τ |
| C. | τ/0.693 |
| D. | 0.693τ |
| Answer» B. 0.5τ | |
| 229. |
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) |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 230. |
An irreversible aqueous phase reaction, A + B → P, is carried out in an adiabatic mixed flow reactor. A feed containing 4 kmole/m³ of each A and B enters the reactor at 8 m³ /hr. If the temperature of the exit stream is never to exceed 390 K, what is the maximum inlet feed temperature allowed?Data: Heat of reaction = - 50 kJ/moleDensity of the reacting mixture = 1000 kg/m³Specific heat of reacting mixture = 2 kJ/kg.K The above data can be assumed to be independent of temperature and composition. |
| A. | 190 |
| B. | 290 |
| C. | 390 |
| D. | 490 |
| Answer» C. 390 | |
| 231. |
In case of unimolecular type elementary reaction given below, plug flow reactor as compared to mixed reactor is |
| A. | more |
| B. | same |
| C. | less |
| D. | unpredictable |
| Answer» B. same | |
| 232. |
If in the gaseous phase reaction, N₂O₄ ↔ 2NO₂, x is the part of N₂O₄ which dissociates, then the number of molecules at equilibrium will be |
| A. | (1 + x) |
| B. | (1 - x) |
| C. | (1 + x)² |
| D. | (1 - x)² |
| Answer» B. (1 - x) | |
| 233. |
Effectiveness factor (E) of a catalyst pellet is defined as below. Effectiveness factor for a first order reaction is given by (where, T = Thiele modulus) |
| A. | tan hT/T |
| B. | tan T/T |
| C. | tan hT/tan T |
| D. | none of these |
| Answer» B. tan T/T | |
| 234. |
At a given temperature, K₁, K₂ and K₃ are equilibrium constants for the following reactions 1, 2, 3 respectively.CH₄(g) + H₂O(g) ↔ CO(g) + 3H₂(g) CO(g) + H₂O(g) ↔ CO₂(g) + H₂(g)CH₄(g) + 2H₂O(g) ↔ CO₂(g) + 4H₂(g)Then K1, K2 and K3 are related as: |
| A. | K₃ = K₁.K₂ |
| B. | K₃ = (K₁.K₂)^0.5 |
| C. | K₃ = (K₁.K₂)/2 |
| D. | K₃ = (K₁.K₂)² |
| Answer» B. K₃ = (K₁.K₂)^0.5 | |
| 235. |
The mean conversion in the exit stream, for a second order, liquid phase reaction in a non-ideal flow reactor is given by |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 236. |
Molecularity of an elementary reaction, P + Q → R + S is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 237. |
For the liquid phase parallel reactions:R, rR = K₁.Cᴀ₂; E₁ = 80 KJ/moleS, rs = K₁.Cᴀ ; E₂ = 120 KJ/mole The desired product is R. A higher selectivity of R will be achieved, if the reaction is conducted at |
| A. | low temperature in a CSTR. |
| B. | high temperature in a CSTR. |
| C. | low temperature in a PFR. |
| D. | high temperature in a PFR. |
| Answer» E. | |
| 238. |
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 |
| Answer» D. 0 | |
| 239. |
A non-catalytic chemical reaction of the following type is called a __________ reaction. |
| A. | parallel |
| B. | series |
| C. | series-parallel |
| D. | none of these |
| Answer» D. none of these | |
| 240. |
The following half life data are available for the irreversible liquid phase reaction A → products. The overall order of reaction is |
| A. | 0.5 |
| B. | 1 |
| C. | 1.5 |
| D. | 2 |
| Answer» D. 2 | |
| 241. |
A second order liquid phase reaction, A → B, is carried out in a mixed flow reactor operated in semi batch mode (no exit stream). The reactant A at concentration CAF is fed to the reactor at a volumetric flow rate of F. The volume of the reacting mixture is V and the density of the liquid mixture is constant. The mass balance for A is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 242. |
What is the order of chemical reaction given below , if it is found that the reaction rate doubles on doubling the concentration of B and also the reaction rate doubles when the concentrations of both A & B were doubled and quandrupled when the concentrations of both B & C were doubled ? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 243. |
The reaction rate constants at two different temperature T₁ and T₂ are related by |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 244. |
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 |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 245. |
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. |
| A. | 100 |
| B. | 150 |
| C. | 200 |
| D. | 225 |
| Answer» B. 150 | |
| 246. |
The conversion for a second order, irreversible reaction (constant volume) given below, in batch mode is given by |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 247. |
The rate controlling step for the heterogeneous irreversible catalytic reaction A(g) + B(g) → C(g) is the surface reaction of absorbed A with absorbed B to give adsorbed C. The rate expression for this reaction can then be written as (where, Kᴀ, Kʙ and Kc are the equilibrium constants and is the rate constant of the rate controlling step.) |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 248. |
If Cᴀ is the quantity of reactants initially present, the quantity left after 'n' half periods will be equal to |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 249. |
For a vapour phase catalytic reaction (A + B → P) which follows the Ridel mechanism and the reaction step is rate controlling, the rate of reaction is given by (reaction rate is irreversible, product also absorbs). |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 250. |
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 following integral is |
| A. | 0 |
| B. | 1 |
| C. | ∞ |
| D. | √2π |
| Answer» C. ∞ | |