This set of Food Processing Unit Operations MCQs focuses on “Contact Equilibrium Separation Process – Extraction and Washing”.
1. What method is used for the separation of organic compound from a mixture of compound?
a) Distillation
b) Extraction
c) Sieving
d) Boiling
View Answer
Explanation: One of the main applications of extraction method is 1. It is used in separation of organic compound from a mixture of the compounds. 2. It selectively dissolves one or more components into ansuitable solvent.
2. What is the principle of solvent extraction?
a) Nernst’s distribution law
b) Henry’s law
c) Raoult’s law
d) Dalton’s law
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Explanation: When the solute is add to a unrelated system of two immiscible liquids, the solute dispenses between the two liquids. This distribution governed by Nernst distribution law.
3. Who discovered extraction?
a) Samuel Percy
b) Fritz Winkler
c) Franz Ritter von Soxhlet
d) Jacques-Arsened’Arsonva
View Answer
Explanation: Samuel Percy invented spray dryer. Fritz Winkler invented fluidized bed dryer. Franz Ritter von Soxhlet discovered extraction. Jacques-Arsened’Arsonva invented freeze dryer.
4. What is not the type of extraction?
a) Liquid/ liquid
b) Liquid/ soild
c) acid/base
d) Gas/gas
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Explanation: Extractions are a way to discrete a desired substance when it is mixed with others. The three most common types of extractions are liquid/liquid, liquid/solid, and acid/base.
5. Which of the following is also known as a chemically active extraction?
a) Liquid/ liquid
b) Liquid/ soild
c) acid/base
d) Gas/gas
View Answer
Explanation: There are three types of extractions; i. Liquid in liquid, ii. Liquid in solid, and iii. Acid in base Acid in base type of extraction is also called as chemically active extraction.
6. What method of extraction is used for fatty acids?
a) Liquid/ liquid
b) Liquid/ soild
c) acid/base
d) Gas/gas
View Answer
Explanation: Liquid/ liquid extraction is used for the extraction of fatty acids. Folch method has been used to extract lipids containing fatty acids from biological samples, using chloroform, water and methanol to separate lipids from aqueous-soluble compounds.
7. How to break emulsion in extraction?
a) By adding NaCl
b) By adding HCl
c) By adding alcohol
d) By adding benzene
View Answer
Explanation: One method that is often used to break up an emulsion is to add some salt like NaCl to increase the ionic strength of the aqueous layer.
8. Which of the following statements about washing are correct?
Statement 1: Unwanted materials must be more soluble in the solvent than in the mixture.
Statement 2: The solvent and mixture must be immiscible.
a) True, False
b) True, True
c) False, True
d) False, False
View Answer
Explanation: Washing is method of selectively removing unwanted compounds from mixture using a solvent. For successful washing, the unwanted materials must be more soluble in the solvent than in the mixture. Moreover, the solvent and mixture must be immiscible.
9. What is the major disadvantage of using ether as an extracting solvent?
a) Highly flammable
b) Highly volatile
c) Highly flammable and highly volatile
d) Cold environment
View Answer
Explanation: The disadvantage of ether is that it is highly volatile and highly flammable. So therefore solvent extraction experiment is conducted in a cold environment and which do not involve heat.
10. Is extraction and washing same?
a) True
b) False
View Answer
Explanation: Extraction is the process where it dissolves the useful material and leaves the others behind whereas washing involves the dissolution of the impurities and leaving the useful material for isolation.
Sanfoundry Global Education & Learning Series – Food Processing Unit Operations.
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