Engineering Questions with Answers - Multiple Choice Questions
Unit Processes MCQ’s – Sulfide Reduction
1 - Question
Why is there a need to add Magnesium salts in Sulfide reduction?
a) Faster reaction
b) Prevents formation of harmful substance
c) Brings equilibrium
d) Lower down the activation energy
View Answer
Explanation: Since the presence of free alkali is harmful, sodium sulfide is not used without the addition of magnesium salts, which remove the sodium hydroxide as it is formed by precipitation of magnesium hydroxide
2 - Question
Why are Alkali reduction most preferred in technical operation?
a) Milder than acid and metal reduction
b) Control degree of reduction
c) Controls the rate
d) All of the mentioned
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Explanation: Alkaline reductions are milder than the iron and acid reductions, and for this reason, modifications of this process find extensive use in technical operations. By utilizing alkali or metal sulphides, it is possible to control better the rate and degree of reduction.
3 - Question
What is/are the important uses of alkali or metal alkali?
a) Preparation of nitroamines from dinitro compounds
b) Reduction of nitrophenols
c) Reduction of nitroanthraquinones
d) All of the mentioned
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Explanation: The important uses of alkali or metal sulphides are: (1) preparation of nitroamines from dinitro compounds, (2) reduction of nitrophenols (3) reduction of nitroanthraquinones, and (4) preparation of aminoazo compounds from the corresponding nitro derivatives.
4 - Question
In which reduction process is there a use of potential difference?
a) Electrolytic reduction
b) Sulphide reduction
c) Electrophilic reduction
d) Amines reduction
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Explanation: In electrolytic reduction we need a power source (such as potential difference) and reductions should be controlled carefully, high yields are often obtained, and by-products are few.
5 - Question
Which one of the following is the electrolyte used in electrolytic reduction?
a) Phenol
b) Sodium hydroxide
c) Amine
d) None of the mentioned
View Answer
Explanation: Electrolytes used in electrolytic reductions are sulfuric acid, hydrochloric acid, sodium hydroxide, inorganic salts, and organic salts.
6 - Question
What is the role of a promoter?
a) Slow down the reaction
b) Inhibits the reaction
c) Increases the catalyst process
d) None of the mentioned
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Explanation: A promoter is an element which increases the reaction rate by promoting the catalyst in lowering the activation energy and hence we can achieve equilibrium faster.
7 - Question
Which one of the following is used as a Cathode electrode?
a) Mercury
b) Copper
c) Iron
d) All of the mentioned
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Explanation: Carbon, copper, zinc, cadmium, mercury, nickel, platinum, lead, tin, amalgamated lead and zinc, and Monel metal have been used as cathodes.
8 - Question
What is the role of an Inhibitor in the chemical reaction?
a) Increase the reaction rate
b) Prevents the reaction
c) Decrease in activation energy
d) All of the mentioned
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Explanation: An inhibitor is an element used to slow down the reaction rate, it is opposite of promoters.
9 - Question
Which factor(s) influence the yield and quantity of the product in Electrolytic reduction?
a) Density
b) Temperature
c) Composition of electrode
d) All of the mentioned
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Explanation: The important factors which influence yield and quality are current density, current concentration, temperature, composition of electrodes, electrolyte, and promoters in an Electrolytic reduction.
10 - Question
Sulfuric acid and arsenic and antimony oxides as promoters in reduction processes.
a) True
b) False
View Answer
Explanation: In electrolytic reductions, sulfuric acid and arsenic and antimony oxide acts as promoters.
11 - Question
What is the formula of Sodium hyposulfite?
a) Na2SO4
b) Na2S2O4
c) Na2S3O4
d) NaS3O3
View Answer
Explanation: The formula of Sodium hyposulfite is Na2S2O4.