Unit Processes Multiple Choice Questions on “Chemical Structures”.
1. How does para-isomers react during Sulfonation reaction?
a) Slowly
b) Rapidly
c) Does not affect
d) None of the mentioned
Answer: a
Clarification: Isomeric compounds show pronounced differences in ease of sulfonation. The para isomer of xylene is more difficult to react; this result is in agreement with the general rule that an entering sulfonate group tends for steric reasons to avoid entering a position adjacent to other substituents, since it is fairly bulky.
2. Which of the following Sulphates fastest?
a) Tertiary
b) Secondary
c) Primary
d) None of the mentioned
Answer: c
Clarification: Sulfation of alcohols with sulfuric acid has shown that primary alcohols sulfate ten times as fast as secondary, because tertiary provides hindrance to reactions.
3. Sulfoalkylating agents are which type of Sulfonate?
a) Inorganic
b) Organic
c) Saturated
d) None of the mentioned
Answer: b
Clarification: Sulfoalklyating agents are called Organic sulfates because they contain one to three carbon atoms and a reactive functional group (e.g., hydroxyl, aldehyde, or olefinic un saturation) allowing easy attachment to an organic compound of higher molecular weight (e.g., a water-insoluble dye) upon which it is desired to confer the properties of a sulfonate group, especially water solubility.
4. Is use of Excessive Sulfonating agents good for industrial processes?
a) Yes
b) No
c) None of the mentioned
d) Depends on other factors
Answer: a
Clarification: Use of excess sulfonating agent does improve the yield and is standard laboratory and industrial practice even though complete reaction is still not achieved.
5. What effect does removal of Sulphuric acid has on Chlorosulfonation reaction?
a) Complete the reaction
b) Increases the activation energy
c) Acts as an inhibitor
d) None of the mentioned
Answer: a
Clarification: Removal of the sulfuric acid formed by chemical means has also been considered as a method for completing the chlorosulfonation reaction.
6. Substitution of the hydrocarbon ring with what increases the ease of sulfonation?
a) Hydroxy group
b) Amino group
c) Alkyl group
d) All of the mentioned
Answer: d
Clarification: Substitution of the hydrocarbon ring with hydroxyl or amino groups, or with successive alkyl groups, increases the ease of sulfonation as reflected by the rate of reaction.
7. Isomeric compounds have no pronounced differences in ease of sulfonation.
a) True
b) False
Answer: b
Clarification: Isomeric compounds show pronounced differences in ease of sulfonation. The para isomer of xylene is more difficult to react than the other two; this result is in agreement with the general rule that an entering sulfonate group tends for steric reasons to avoid entering a position adjacent to other substituents, since it is fairly bulky.
8. What prevents the formation of Sulfonated compounds with SO3?
a) Mercury catalyst
b) Steric hindrance
c) All of the mentioned
d) None of the mentioned
Answer: b
Clarification: Steric hindrance prevents formation of the difficultly sulfonatable addition compound with S03.
9. Which compound state is the most difficult to Sulfonate?
a) Primary
b) Secondary
c) Tertiary
d) None of the mentioned
Answer: c
Clarification: A study of the sulfation of alcohols with sulfuric acid has shown that primary alcohols sulphate ten times as fast as secondary. Therefore tertiary compounds are the most difficult to sulfonate.
10. Does Time of the reaction has any effect on efficiency of reaction?
a) Yes
b) No
c) None of the mentioned
d) Doesn’t depend on it
Answer: a
Clarification: To obtain maximum efficiency in commercial sulfonation and sulfation, the reaction time must be reduced to the minimum compatible with product quality and yield.
11. Low temperatures with correspondingly long reaction periods is more useful.
a) True
b) False
Answer: a
Clarification: Low temperatures with correspondingly long reaction periods tend to yield purer and lighter-coloured products.
12. Reaction temperature is often important in determining which ratio?
a) Mono- to polysulfonates
b) Mono- to Disulphates
c) Poly- to monosulfonates
d) All of the mentioned
Answer: a
Clarification: Reaction temperature is often important in determining the ratio of mono- to polysulfonates.