Engineering Questions with Answers - Multiple Choice Questions
Unit Processes MCQ’s – Esterification by Organic Acids
1 - Question
What are the constituents of ester?
a) Hydrogen
b) Ionized hydrogen
c) Only aromatic
d) All the mentioned
View Answer
Explanation: An ester is usually defined as a compound formed by substituting an organic radical for an ionisable hydrogen of an acid.
2 - Question
Why is there a selectivity in bond breaking process?
a) Reactants
b) Catalyst
c) Electronic structure
d) All of the mentioned
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Explanation: the selectivity of the bond-breaking process is found in the electronic structure of the reactants and products. Since oxygen is more electronegative than carbon, the carbonyl carbon is more positive than the carbonyl oxygen.
3 - Question
Oxygen is more electropositive than carbon.
a) True
b) False
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Explanation: Since oxygen is more electronegative than carbon, the carbonyl carbon is more positive than the carbonyl oxygen.
4 - Question
What is meant by equilibrium constant ‘k’ of the reaction?
a) (ester*water)/ (Acid*alcohol)
b) (Ester*alcohol)/ (Acid*water)
c) (Acid*water)/ (ester*alcohol)
d) None of the mentioned
View Answer
Explanation: The equilibrium constant for the reaction is (ester*water)/ (Acid*alcohol), the value of K changes with the presence of salts.
5 - Question
Which of the following has the highest initial rate?
a) Ethyl
b) Methyl
c) Propyl
d) All of the mentioned
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Explanation: The primary alcohols, ethyl, propyl, and butyl, have approximately the same initial rates and limits but are inferior to methyl alcohol in both of these respects.
6 - Question
What type of effect does the phenyl group in benzyl alcohol has?
a) Positive effect
b) Ionic effect
c) Retarding influence
d) None of the mentioned
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Explanation: The presence of the phenyl group in benzyl alcohol has a retarding influence.
7 - Question
Esters can decompose to from what?
a) Base
b) Unsaturated hydrocarbon
c) Saturated hydrocarbon
d) All of the mentioned ab
View Answer
Explanation: the esters can decompose to form an unsaturated hydrocarbon and the acid.
8 - Question
Which one of the following has the slowest esterification rate?
a) Primary
b) Secondary
c) Tertiary
d) All the mentioned
View Answer
Explanation: It is stated that the more branched the carbon chain of the alcohol and the nearer the branches are to the hydroxyl group, the slower will be its esterification and the lower the limit. These effects are due to steric hindrance to the approach of the alcohol to the acid molecule.
9 - Question
In acids, low rate of esterification and a low limit of reaction go together.
a) True
b) False
View Answer
Explanation: with the alcohols, low rate of esterification and a low limit of reaction go together, it is quite otherwise with the acids. The esterification of the unsaturated acids, cinnamic and sorbic, starts off much more slowly than that of the corresponding saturated acids but goes somewhat faster. Formic acid, which has an extremely high initial rate, has a relatively low limit.
10 - Question
Formic acid, which has an extremely high initial rate.
a) True
b) False
View Answer
Explanation: Formic acid, which has an extremely high initial rate, has a relatively low limit.