Unit Processes MCQ Set 1
1. Methane can be obtain from synthesis gas over which catalyst?
a) Aluminium
b) Zinc
c) Nickel
d) All of the mentioned
Answer
Answer: c [Reason:] High-Btu gas consisting principally of methane can be produced by conversion of synthesis gas over nickel or iron catalysts; nickel is more active.
2. What is the ratio of feed gas H2: CO?
a) 1:2
b) 1:3
c) 2:1
d) 3:1
Answer
Answer: d [Reason:] Four volumes of synthesis gas is consumed per volume of methane formed. A feed gas of 3H2: 1CO ratio is desirable in accordance with the reaction.
3. Which type of reaction is methanation?
a) Endothermic
b) Exothermic
c) Neutral
d) None of the mentioned
Answer
Answer: b [Reason:] Methanation is highly exothermic, there being an evolution of 49.27 kcal per mole (29S.2°K) of methane.
4. Difficulty was encountered in gasifying non-caking coals.
a) True
b) False
Answer
Answer: b [Reason:] Difficulty was encountered in gasifying caking coals, but not non caking fuels.
5. What is the advantage of fluid bed catalyst in methanation?
a) Fast reaction
b) High temperature
c) Remove heat
d) Supplies heat
Answer
Answer: c [Reason:] The advantage of this technique is that only small amounts of end gas need be recycled to remove the heat of reaction because of the relatively high heat transfer obtained in the fluid bed.
6. Which process is related to Fischer-Tropsch process?
a) Oxo
b) Synol
c) Isosynthe
d) All of the mentioned
Answer
Answer: d [Reason:] Three processes, the Oxo, Synol, and Isosynthe are related to the Fischer-Tropsch process in that hydrocarbons or oxygated chemicals are produced from mixtures of hydrogen and carbon monoxide.
7. What is the chief products of the Oxo and Synol processes?
a) Alcohols
b) Aromatics
c) Ketones
d) Amides
Answer
Answer: a [Reason:] Aliphatic oxygenated compounds, mainly alcohols are the chief products of the Oxo and Synol processes.
8. What is produced in Oxo process?
a) Alcohols
b) Aldehydes
c) Ketones
d) Carboxylic acid
Answer
Answer: b [Reason:] This reaction of an olefin with hydrogen and carbon monoxide in the presence of a cobalt catalyst to produce aldehydes, containing one carbon atom more than that of the hydrocarbon in the feed.
9. The Oxo process is also called what?
a) Hydrofromylation
b) Hydrogenation
c) Hydrochlorination
d) None of the mentioned
Answer
Answer: a [Reason:] The reaction results in the addition of a hydrogen atom and the formyl group (CHO) to the double bond, it would more properly be called hydroformylation.
10. The aldehyde in Oxo process is reduced to what?
a) Primary alcohol
b) Secondary alcohol
c) Tertiary alcohol
d) All of the mentioned
Answer
Answer: a [Reason:] The commercial process of Oxo process involves a second step in which aldehydes are reduced with hydrogen to primary alcohols.
11. What is the ratio of Synthesis gas in Oxo process?
a) 1:3
b) 1:2
c) 1:1
d) 3:1
Answer
Answer: c [Reason:] Synthesis gas and an olefin are the reactants of the Oxo process. The ratio of H2: CO is usually 1: 1.
12. Which catalyst is used for Oxo process?
a) Nickel
b) Cobalt
c) Iron
d) All of the mentioned
Answer
Answer: b [Reason:] Cobalt catalysts are universally used for the Oxo reaction.
13. How does low-molecular weight olefins react at low temperature?
a) Slowly
b) Moderately
c) Rapidly
d) None of the mentioned
Answer
Answer: c [Reason:] Low-molecular-weight olefins react at lower temperatures and more rapidly than do the higher-molecular-weight olefins.
14. For maximum yield of Oxo process, at what temperature it should react?
a) High
b) Low
c) Moderate
d) None of the mentioned
Answer
Answer: b [Reason:] For maximum yield of aldehydes, the reaction should be operated at as Iow temperature as is compatible with a reasonable reaction rate.
Unit Processes MCQ Set 2
1. Hydrogenation refers to the introduction of which molecule?
a) Oxygen
b) Hydrogen
c) Amine
d) Nitrogen
Answer
Answer: b [Reason:] Hydrogenation is a process in which hydrogen atom is introduced in the molecule during reaction in presence of a catalyst.
2. What is meant by hydrogenolysis?
a) Addition of hydrogen
b) Cleaved by hydrogen
c) Removing hydrogen
d) None of the mentioned
Answer
Answer: b [Reason:] The reactions in which molecules are cleaved by hydrogenis known as hydrogenolysis or destructive hydrogenation.
3. Which of the following reaction(s) involves molecular hydrogen?
a) Hydroammonolysis
b) Hydroformylation
c) Hydrogenation
d) All of the mentioned
Answer
Answer: d [Reason:] Reactions which involve molecular hydrogen and catalysts are reductive amination (hydroammonolysis), hydroformylation (Oxo and Oxoyl reactions), and the synthesis of ammonia.
4. Hydrogenation can be synonym for which other process?
a) Oxidation
b) Neutralization
c) Reduction
d) Dehydrogenation
Answer
Answer: c [Reason:] Hydrogenation, in the exact usage of the designation, is synonymous with reduction, which is the term usually applied to a reaction in which oxygen or some other element (most commonly nitrogen, sulphur, carbon, or halogen) is withdrawn from or hydrogen is added to a molecule.
5. What are the other types of reduction?
a) Metals in acid
b) Electrolysis
c) Metal hydride
d) All of the mentioned
Answer
Answer: d [Reason:] Important methods of reduction other than catalytic hydrogenation are: (1) by metals in acid or basic solution, (2) by alkali metals in alcoholic solution, (3) by electrolysis, (4) by alkali metals and hydrazine, (5) by complex metal hydrides, and (6) by hydrogen transfer.
6. Is hydrogen transfer and catalytic hydrogenation same?
a) Yes
b) No
Answer
Answer: a [Reason:] Of the above methods the one most frequently confused with catalytic hydrogenation is hydrogen transfer, which involves the saturation of ethylenic double bonds by the direct exchange of hydrogen generally from one substance to another with essentially no participation of free molecular hydrogen. The process is recognized as being separate and distinct from hydrogenation or dehydrogenation and apparently proceeds by an ionic mechanism taking place over an acid catalyst.
7. Hydrogenation cannot be used to convert liquid fats to solid fats.
a) True
b) False
Answer
Answer: b [Reason:] Technical application of hydrogenation was in the reduction of the double bonds between two carbon atoms for the purpose of converting liquid fats into solid fats, or as it is often called fat hardening.
8. Which type of hydrogenation is used in petroleum processing?
a) Low
b) Mild
c) High
d) None of the mentioned
Answer
Answer: b [Reason:] Mild hydrogenation is being used extensively in petroleum processing, especially in product finishing of naphtha, kerosene, diesel fuel, heating oil, and distillate lubricating oils.
9. What is meant by Fat hydrogenation?
a) Liquid to solid fat
b) Adding H to Aromatics
c) Adding H to fatty acid
d) All of the mentioned
Answer
Answer: c [Reason:] Fat hydrogenation, the addition of hydrogen to fatty acids-particularly edible oils such as cottonseed and soybean-although accounting for less than one per cent by weight of the oil, is an important outlet for hydrogen.
10. Catalytic hydrogenation has been applied to materials of widely varying molecular weights and structures.
a) True
b) False
Answer
Answer: a [Reason:] Catalytic hydrogenation has been applied to materials of widely varying molecular weights and structures. Thus, materials such as wood, rubber, vitamins, proteins, steroids, elastomers, cotton linters, and nylon are typical of the variety of compounds subjected to the reaction.
Unit Processes MCQ Set 3
1. Back mixing can occur only in ___ in a chemical process.
a) Stagnant reaction
b) Flow reaction
c) Both the reactions
d) Does not depend on it
Answer
Answer: b [Reason:] Back mixing is the mixing of reactants and products due to flow reaction. It happens in horizontal direction and it reduces the product quality.
2. How many types of reactors are there?
a) 2
b) 3
c) 4
d) Many number
Answer
Answer: c [Reason:] There are 4 types of reactors: simple batch homogeneous, semi batch, Continuous homogeneous and continuous heterogeneous reactors.
3. In which reactor one reactant is feed and other reactant is added continuously?
a) Simple batch reactor
b) Semi batch reactor
c) Continuous homogeneous reactor
d) Continuous heterogeneous reactor
Answer
Answer: b [Reason:] In Semi batch reactor, it is a type of reactor in which one reactant is already added and another one is continuously added.
4. When a large volume is there, what type of reactor is used?
a) Tubular reactor
b) Simple batch reactor
c) Semi batch reactor
d) Tower reactor
Answer
Answer: d [Reason:] Whenever a large volume is there for reaction we use tower reactor. It further consists of empty, packed and baffled tower reactors.
5. Which tower has a horizontal tank, with low ratio of length to diameter?
a) Baffled tank reactor
b) Tower reactor
c) Longitudinal reactor
d) All of the mentioned
Answer
Answer: a [Reason:] Only baffled tank has a low length to diameter ratio, and is horizontal in shape.
6. Which reactor has zero back mixing?
a) Tubular reactor
b) Longitudinal reactor
c) Semi batch reactor
d) All of the mentioned
Answer
Answer: b [Reason:] Only longitudinal reactor has zero back mixing as the reaction takes place only in one direction and not laterally.
7. What %cent age back mixing takes place in a Stirred tank reactor?
a) 100%
b) 75%
c) 50%
d) 0%
Answer
Answer: a [Reason:] Only in a Stirred tank reactor we get 100% back mixing. Hence is has a very low yield.
8. What is the other name of series reaction?
a) Complex reaction
b) Parallel reaction
c) Consecutive reaction
d) None of the mentioned
Answer
Answer: c [Reason:] The other name of Series reaction is Consecutive reaction.
9. For a large scale production, which reactor is preferable?
a) Batch reactor
b) Semi batch reactor
c) Continuous reactor
d) None of the mentioned
Answer
Answer: c [Reason:] For a large amount of production i.e high yield, a continuous reactor is always preferred.
10. For a high degree of agitation, which reactor is used?
a) Stirred tank
b) Tubular reactor
c) Longitudinal reactor
d) All of the mentioned
Answer
Answer: a [Reason:] For high amount of agitation a stirred tank is used because it provides fast reaction. Mechanical agitators are employed in it to provide agitation.
Unit Processes MCQ Set 4
1. What is/are the application of German fixed-bed reactor?
a) Heat removal
b) Complex design
c) Low capacity
d) All of the mentioned
Answer
Answer: d [Reason:] Germany employed a fixed bed of granular or extruded catalyst. In order to provide adequate cooling surface for heat removal, the reactors were of a complex design and of low capacity.
2. What is the drawback if German fixed-bed reactor?
a) Heat removal
b) High contact area
c) High cost
d) All of the mentioned
Answer
Answer: c [Reason:] In German fixed-bed reactor, low output and complex fabrication, the fixed cost per unit of product was quite high. Other types of reactors were developed because of these inherent drawbacks.
3. Synthesis with a slurried catalyst has been investigated in which type of plants?
a) Small
b) Moderate
c) Large
d) None of the mentioned
Answer
Answer: c [Reason:] Slurry, synthesis with a slurried catalyst has been investigated in large pilot plants.
4. What does slurry consists of?
a) Fine particles
b) Pulverized particles
c) Large particles
d) All of the mentioned
Answer
Answer: b [Reason:] The slurry consists of finely pulverized catalyst particles suspended in a high-boiling oil to which the heat of reaction is transferred.
5. The oil-circulation process is similar to which process?
a) Slurry process
b) German fixed-bed process
c) Both of the mentioned
d) None of the mentioned
Answer
Answer: b [Reason:] The oil-circulation process is similar to the slurry system in that the catalyst is submerged in a high-boiling oil which serves to remove the heat of reaction and permit close control of the temperature.
6. What is the size of particles in Oil circulation?
a) Fine particles
b) Moderate size
c) Large size
d) None of the mentioned
Answer
Answer: c [Reason:] In oil circulation, larger catalyst particles are used, either granules or massive iron or steel such as shot or lathe turnings.
7. Which synthesis process is similar to catalytic cracking of hydrocarbons?
a) Slurry process
b) German fixed-bed
c) Oil circulation
d) Fluid bed process
Answer
Answer: d [Reason:] Synthesis in a fluid bed of catalyst, in a manner similar to that employed for catalytic cracking of hydrocarbons.
8. What is meant by ‘Hot gas recycle’?
a) Removal of heat
b) Supplying heat
c) Reflux heat
d) None of the mentioned
Answer
Answer: a [Reason:] In Hot-gas Recycle, removal of the heat of reaction as sensible heat of fresh feed and recycle gas is utilized in the hot-gas-recycle system.
9. The shape and size of catalyst is not very important.
a) True
b) False
Answer
Answer: b [Reason:] The shape and size of the catalyst must be designed to avoid excessive pressure drop and high costs for circulating gas.
10. What happens to the velocity of gas, as heat-transfer coefficients increases?
a) Increases
b) Decreases
c) No change
d) None of the mentioned
Answer
Answer: a [Reason:] As linear velocity of the gas is higher, greater heat-transfer coefficients are obtained.
11. Heat removal can only be done directly.
a) True
b) False
Answer
Answer: b [Reason:] Heat removal for the most part may be considered to take place either directly, as in the oil- or gas-cooled systems where the catalyst surface .s in contact with the cooling medium, or indirectly, as in the fixed or fluid beds where heat must be transferred through the bed to a cooling surface.
12. What happens when the reaction occurs non-uniformly?
a) High gradient
b) Low gradient
c) Small yield
d) Less conversion
Answer
Answer: a [Reason:] A uniform amount of reaction has been assumed through the catalyst bed. When the reaction occurs non uniformly and a large amount of conversion takes place in a limited area, as is often the case near the point of entry of the fresh gas, the gradients are higher.
13. Lower gradients ensure better temperature control.
a) True
b) False
Answer
Answer: a [Reason:] Lower gradients ensure better temperature control and freedom from overheating.
Unit Processes MCQ Set 5
1. Why is there a need to add Magnesium salts in Sulfide reduction?
a) Faster reaction
b) Prevents formation of harmful substance
c) Brings equilibrium
d) Lower down the activation energy
Answer
Answer: b [Reason:] Since the presence of free alkali is harmful, sodium sulfide is not used without the addition of magnesium salts, which remove the sodium hydroxide as it is formed by precipitation of magnesium hydroxide.
2. Why are Alkali reduction most preferred in technical operation?
a) Milder than acid and metal reduction
b) Control degree of reduction
c) Controls the rate
d) All of the mentioned
Answer
Answer: d [Reason:] Alkaline reductions are milder than the iron and acid reductions, and for this reason, modifications of this process find extensive use in technical operations. By utilizing alkali or metal sulphides, it is possible to control better the rate and degree of reduction.
3. What is/are the important uses of alkali or metal alkali?
a) Preparation of nitroamines from dinitro compounds
b) Reduction of nitrophenols
c) Reduction of nitroanthraquinones
d) All of the mentioned
Answer
Answer: d [Reason:] The important uses of alkali or metal sulphides are: (1) preparation of nitroamines from dinitro compounds, (2) reduction of nitrophenols (3) reduction of nitroanthraquinones, and (4) preparation of aminoazo compounds from the corresponding nitro derivatives.
4. In which reduction process is there a use of potential difference?
a) Electrolytic reduction
b) Sulphide reduction
c) Electrophilic reduction
d) Amines reduction
Answer
Answer: a [Reason:] In electrolytic reduction we need a power source (such as potential difference) and reductions should be controlled carefully, high yields are often obtained, and by-products are few.
5. Which one of the following is the electrolyte used in electrolytic reduction?
a) Phenol
b) Sodium hydroxide
c) Amine
d) None of the mentioned
Answer
Answer: b [Reason:] Electrolytes used in electrolytic reductions are sulfuric acid, hydrochloric acid, sodium hydroxide, inorganic salts, and organic salts.
6. What is the role of a promoter?
a) Slow down the reaction
b) Inhibits the reaction
c) Increases the catalyst process
d) None of the mentioned
Answer
Answer: c [Reason:] A promoter is an element which increases the reaction rate by promoting the catalyst in lowering the activation energy and hence we can achieve equilibrium faster.
7. Which one of the following is used as a Cathode electrode?
a) Mercury
b) Copper
c) Iron
d) All of the mentioned
Answer
Answer: a [Reason:] Carbon, copper, zinc, cadmium, mercury, nickel, platinum, lead, tin, amalgamated lead and zinc, and Monel metal have been used as cathodes.
8. What is the role of an Inhibitor in the chemical reaction?
a) Increase the reaction rate
b) Prevents the reaction
c) Decrease in activation energy
d) All of the mentioned
Answer
Answer: b [Reason:] An inhibitor is an element used to slow down the reaction rate, it is opposite of promoters.
9. Which factor(s) influence the yield and quantity of the product in Electrolytic reduction?
a) Density
b) Temperature
c) Composition of electrode
d) All of the mentioned
Answer
Answer: d [Reason:] The important factors which influence yield and quality are current density, current concentration, temperature, composition of electrodes, electrolyte, and promoters in an Electrolytic reduction.
10. Sulfuric acid and arsenic and antimony oxides as promoters in reduction processes.
a) True
b) False
Answer
Answer: a [Reason:] In electrolytic reductions, sulfuric acid and arsenic and antimony oxide acts as promoters.
11. What is the formula of Sodium hyposulfite?
a) Na2SO4
b) Na2S2O4
c) Na2S3O4
d) NaS3O3
Answer
Answer: b [Reason:] The formula of Sodium hyposulfite is Na2S2O4.
