This set of Unit Processes Multiple Choice Questions & Answers (MCQs) focuses on “Esterification of Carboxylc acid and Derivatives – I”.
1. What is the other name of ester-interchange reaction?
a) Ketonolysis
b) Alcoholysis
c) Aldehyde
d) None of the mentioned
View Answer
Explanation: In the alcoholysis or ester-interchange reaction, an alcohol reacts with an ester to give a new ester.
2. Complete the following reaction: CH3COOC2H5 + HOCH3 ——> _______ + HOC2H5.
a) CH3COCH3
b) CH3COCH2CH3
c) CH3COOCH3
d) CH3COOCH2
View Answer
Explanation: The following reaction is ester-interchange reaction, CH3COOC2H5 + HOCH3 ——> CH3COOCH3 + HOC2H5.
3. A mixture of amyl nitrite and ethyl alcohol produces what?
a) Nitrile
b) Nitrosamine
c) Nitro ethyl alcohol
d) Ethyl nitrite
View Answer
Explanation: If a mixture of amyl nitrite and ethyl alcohol containing an acid catalyst is warmed, ethyl nitrite distils out.
4. Which is the commonly used catalysts for alcoholysis?
a) Aluminium oxide
b) Sodium alkoxides
c) Iron oxide
d) All of the mentioned
View Answer
Explanation: The most commonly used catalysts for alcoholysis, however, are the sodium alkoxides.
5. How to increase the rate in alcoholysis?
a) Increase basicity
b) Attack on positive carbonyl carbon
c) Catalyst
d) All of the mentioned
View Answer
Explanation: For the increase in rate is that the basicity of the alcohol oxygen is increased and that this increase in basicity facilitates attack on the positive carbonyl carbon.
6. Which of the following acts as a catalyst in alcoholysis reaction?
a) Ammonia
b) Pyridine
c) Sodium hydroxide
d) All of the mentioned
View Answer
Explanation: Besides the sodium alkoxides, various other catalysts for this reaction have been recommended: ammonia, pyridine, tetramethylammonium hydroxide, aluminium alkoxides,l lithium methoxide, sodium hydroxide, and sodium carbonate.
7. Titanium esters are excellent esterexchange catalysts.
a) True
b) False
View Answer
Explanation: Titanium esters are excellent esterexchange catalysts. They are effective in catalysing interchange between two esters as well as between an alcohol and an ester. They usually do not catalyse side reactions, and they are especially useful with polymerizable materials such as methacrylates which are attacked or polymerized by standard ester-exchange catalysts.
8. What is the counterpart of alcoholysis called?
a) Acidolysis
b) Aldehyde
c) Both acidolysis and aldehyde
d) None of the mentioned
View Answer
Explanation: The counterpart of alcoholysis, acidolysis, in which one acid displaces another from an ester is so similar to alcoholysis that little need be said about it.
9. How is reactions of an alcohol with acetic anhydride are accelerated?
a) Sulfuric acid
b) Zinc chloride
c) Phosphorus pentoxide
d) All of the mentioned
View Answer
Explanation: Reactions of an alcohol with acetic anhydride are greatly accelerated by acid catalysts, such as sulfuric acid, zinc chloride, phosphorus pentoxide, ferric chloride, etc.
10. What is the disadvantage of Acid chloride?
a) Evolution of HCl
b) Corrosive
c) Evolution of HCl and Corrosive
d) None of the mentioned
View Answer
Explanation: The disadvantages of acid chloride are that the hydrogen chloride evolution can cause changes in the organic compounds or serious corrosion of metal equipment.
11. What do we get on mixing NH3 with ester?
a) Amide
b) Alcohol
c) Acid amide
d) None of the mentioned
View Answer
Explanation: An excellent way to make an acid amide is to treat an ester with ammonia.
12. What type of reaction is Esterification of Amides?
a) Irreversible
b) Reversible
c) Reaction doesn’t take place
d) None of the mentioned
View Answer
Explanation: Esterification of Amides is a reversible reaction.
13. What type of reaction is Esterification of Amides?
a) Endothermic
b) Exothermic
c) Neutral
d) None of the mentioned
View Answer
Explanation: When a high-boiling alcohol is used, the ammonia can be driven off by heating. Since the reaction is endothermic, high temperatures thermodynamically favour alcoholysis of the amide.
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