Unit Processes Quiz on “Hydrogen : Introduction”.
1. Hydrogenation refers to the introduction of which molecule?
a) Oxygen
b) Hydrogen
c) Amine
d) Nitrogen
Answer: b
Clarification: 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: b
Clarification: 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: d
Clarification: 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: c
Clarification: 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applied to a reaction in which oxygen or some other element (most commonly nitrogen, sulphur, carbon, or halogen) is withdrawn from or hydrogen is added to a molecule.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: d
Clarification: 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: a
Clarification: 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: b
Clarification: 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: b
Clarification: 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: c
Clarification: 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: a
Clarification: 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.