This set of Unit Processes Multiple Choice Questions & Answers (MCQs) focuses on “Hydrolysing Agents”.
1. Which of the following is readily hydrolysed by water?
a) Acid anhydrides
b) Amides
c) Nitrites
d) All of the mentioned
View Answer
Explanation: The acid anhydrides, lactones, lactides, and other internal anhydrides such as ethylene oxide are readily hydrolysed by water alone, acetic anhydride reacting much more rapidly than either benzoic or phthalic.
2. What is meant by mixed anhydride?
a) Slow hydrolysis
b) Controlling hydrolysis
c) Vigorous hydrolysis
d) None of the mentioned
View Answer
Explanation: Mixed anhydrides, among which, for convenience, are included the acid halides, react with vigour, especially acetyl chloride, which is more reactive than acetic anhydride itself. In general, the stronger the two acids in these mixed anhydrides, the more vigorous the hydrolysis.
3. Which of the following is most reactive in hydrolysis?
a) Butyryl bromide
b) Benzoyl chloride
c) Acetic anhydride
d) Acetyl chloride
View Answer
Explanation: Here acetyl chloride is more reactive than acetic anhydride, acetyl chloride is more readily hydrolysed than butyryl bromide. Benzoyl chloride, however, reacts with less readiness than acetyl chloride, despite the greater strength (dissociation) of benzoic acid.
4. Benzoyl chloride, reacts with less readiness than acetyl chloride, despite having greater strength, why?
a) High dissociation
b) Lower solubility
c) Steric hindrance
d) All of the mentioned
View Answer
Explanation: Benzoyl chloride, however, reacts with less readiness than acetyl chloride, despite the greater strength (dissociation) of benzoic acid. This is probably due to the lower solubility of benzoyl chloride in water.
5. Why is sulphuric acid reacts with which type of compounds?
a) Organic substances
b) Intermediate compounds
c) Both of the mentioned
d) None of the mentioned
View Answer
Explanation: Sulfuric acid is particularly useful because it forms, with many types of organic substances, intermediate compounds that themselves readily undergo hydrolysis. In all these, sulfuric acid exhibits a specific action, distinct from its hydrogen-ion concentration, and cannot be replaced by other acids.
6. The action of acid on acetoacetic ester produces what?
a) Carbonic acid
b) Acetone
c) Alcohols
d) All of the mentioned
View Answer
Explanation: The action of acid on acetoacetic ester and its derivatives leads to acetone, carbonic acid, and alcohol and its related products, while alkali on the same ester produces acetic acid and alcohol.
7. Alkali is used only to a limited extent in the hydrolysis of carbohydrates.
a) True
b) False
View Answer
Explanation: Alkali is used only to a limited extent in the hydrolysis of carbohydrates. Cellulose is rather resistant to alkali and, when attacked, is broken down but not distinctly hydrolysed.
8. Molasses is converts to alcohol in presence of what?
a) Water
b) Alkali chlorine
c) Invertase
d) All of the mentioned
View Answer
Explanation: Molasses is converted by invertase in the manufacture of industrial alcohol, and, of course, the whole brewing industry depends upon the complex hydrolysis of starch into maltose and glucose by the amylases.
9. Which ion hydrolysis the reaction in alkali hydrolysis?
a) Alkali ion
b) Hydronium ion
c) Both alkali and hydronium ion
d) None of the mentioned
View Answer
Explanation: The use of low concentrations of alkali in the hydrolysis of esters and similar materials: Here the hydroxyl ion is supposed to catalyse the reaction as the hydrogen ion does in catalysis by dilute acid.
10. Alkyl halides of complex composition react with water alone.
a) True
b) False
View Answer
Explanation: Alkyl halides of complex composition react with water alone, though the simple halides like ethyl chloride are but slightly affected.
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