This set of Unit Processes Multiple Choice Questions & Answers (MCQs) focuses on “Catalyst and Sulfonating agents”.
1. The addition of mercury changes the orientation in a number of aromatic sulfonation reactions.
a) True
b) False
View Answer
Explanation: The addition of mercury changes the orientation in a number of aromatic sulfonation reactions. This is of great practical importance especially with anthraquinone, since in the presence of the catalyst the a-sulfonate is formed almost exclusively, while without mercury only the, B-sulfonate is obtained.
2. R-HgSO4H + SO3 ——> RSO3H + HgSO4. Which type of reaction is the following?
a) Substitution reaction
b) Replacement reaction
c) Addition reaction
d) None of the mentioned
View Answer
Explanation: The above organic mercurial intermediate which is formed, the compound actually undergoing a replacement-type sulfonation.
3. Mercury catalyst does not function with which compound?
a) Aqueous acid
b) SO3
c) Oleum
d) All of the mentioned
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Explanation: Mercury functions catalytically only when using oleum or SO3 as the sulfonating agent. It does not function with aqueous acid, the use of which presumably inhibits one of the intermediate steps.
4. Mercury affects the orientation of which of the following compounds?
a) Nitrobenzene
b) Benzene sulfonic acid
c) O-xylene
d) All of the mentioned
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Explanation: Mercury affects the orientation of other organic compounds than anthraquinone, including: benzoic acid, phthalic anhydride, a-naphthol, nitrobenzene, benzenesulfonic acid, o-xylene, and chloroanthraquinones.
5. Mercury can also increase the yield without changing the orientation.
a) True
b) False
View Answer
Explanation: Mercury is sometimes used to increase the yield in certain difficult sulfonations, but without changing the orientation.
6. What effect does addition of Catalyst has on the sulfonation reaction?
a) Lowers reaction temp.
b) Improves yield
c) Accelerates reaction
d) All of the mentioned
View Answer
Explanation: The addition of catalysts sometimes allows the use of lower reaction temperatures, improves yields, accelerates reaction, or in some cases even renders reaction possible.
7. Which of the following compound inhibits sulfone formation?
a) Acetic acid
b) Mercury
c) Sulphuric acid
d) None of the mentioned
View Answer
Explanation: The addition of acetic acid inhibits, but does not eliminate, sulfone formation. Sodium sulphate and sodium benzenesulfonate are also said to inhibit sulfone formation from benzene.
8. Why is the use of reaction solvents is important?
a) Efficient mixing
b) Uniform reaction
c) Reduce reaction temperature
d) Both efficient mixing and uniform reaction
View Answer
Explanation: The use of reaction solvents is therefore often either essential or preferable to obtain efficient mixing, thereby ensuring uniform reaction.
9. Which compound is used for ‘Baking process’ of sulfonating aromatic amines?
a) Ortho-dichlorobenzene
b) Para-dichlorobenzene
c) Meta-dichlorobenzene
d) All of the mentioned
View Answer
Explanation: Ortho-dichlorobenzene or similar compounds are used in a modified form of the “baking process” for sulfonating aromatic amines.
10. Which one of the following is a property of Chlorinated solvents?
a) High-boiling
b) Relatively inert
c) Inexpensive
d) All of the mentioned
View Answer
Explanation: Chlorinated Solvents are high-boiling, relatively inert, inexpensive, and are immiscible with water.
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