Engineering Questions with Answers - Multiple Choice Questions
Unit Processes MCQ’s – Physical and Chemical Factors
1 - Question
In SO3 reaction, which is/are the important variable that determines the rate and course of the reaction?
a) Solvent
b) Catalyst
c) Chemical structure
d) All of the mentioned
View Answer
Explanation: When employing SO2 or its compounds for sulfonation or sulfation, important variables determining the rate and course of the reaction are (1) concentration of SO3 in the sulfonating agent, (2) chemical structure of the organic compound, (3) time in relation to temperature and reagent strength, (4) catalysts, and (5) solvents.
2 - Question
Sulphuric acid and oleum are also called ______ of SO3.
a) Hydrates
b) Alcohol
c) Amines
d) Oxides
View Answer
Explanation: the hydrates of SO3 (i.e., sulfuric acid and oleum) are properly regarded as solutions of SO3 in water.
3 - Question
What happens to the rate of Sulfonation, if concentration of water decreases?
a) Increases
b) Decreases
c) Both of these
d) Does not depend on it
View Answer
Explanation: As the concentration of water increases, the rate of sulfonation steadily decreases, since the reaction rate is inversely proportional to the square of the water concentration.
4 - Question
Complete the following reaction: RH + H2SO4 ——-> _______ + H2O.
a) RSOH
b) RSO2H
c) RSO3H
d) None of the mentioned
View Answer
Explanation: The following reaction is known as Hydrates of SO3, and the reaction is as: RH + H2SO4 ——-> RSO3H + H2O.
5 - Question
Excess acid can be used to achieve maximum completion of reaction.
a) True
b) False
View Answer
Explanation: Excess acid is also used to achieve maximum completion of reaction in the sulfation of alcohols. Thus, lauryl alcohol is reacted to the extent of 90 per cent by employing a 70 per cent excess of monohydrate acid, Oleum gives excessive decomposition.
6 - Question
What is meant by ‘Baking process’?
a) Forward reaction
b) Continous heat
c) Evaporation of water
d) All of the mentioned
View Answer
Explanation: In the baking procedure, water is removed at high temperature by circulating air or by the use of vacuum.
7 - Question
Why do we add BF3 in Sulfonation reactions?
a) Completes the reaction
b) Forward the reaction
c) Removes water
d) All of the mentioned
View Answer
Explanation: Sulfonation can also be completed by adding to the sulfonation mixture a material capable of reacting with the water formed, thereby removing it and allowing this reaction to go to completion. The introduction of BFa accomplishes this.
8 - Question
What is the formula of thionyl chloride?
a) SO2Cl
b) SOCl2
c) SCl3
d) None of the mentioned
View Answer
Explanation: The formula of thionyl chloride is SOCl2, which also used for the removal of water in sulfonation reaction.
9 - Question
Formation of the sulfuric acid by chemical means has also been considered as a method for completing the chlorosulfonation reaction.
a) True
b) False
View Answer
Explanation: Removal of the sulfuric acid formed by chemical means has also been considered as a method for completing the chlorosulfonation reaction, this way the reaction moves in forward direction.
10 - Question
Which of the following compounds make Sulfonation difficult?
a) Halogen compounds
b) Nitro compounds
c) Carbonyl compounds
d) All of the mentioned
View Answer
Explanation: Halogen, nitro, carbonyl, and sulfonyl groups make sulfonation more difficult. It will therefore be seen that (aside from halogen which is only mildly deactivating) ortho-para directing groups facilitate ring sulfonation, while meta directing groups hinder sulfonation.