Engineering Chemistry Questions and Answers for Experienced people focuses on “Oils and Fats – 2”.
1. The catalyst used in the addition of iodine is ____________
a) Ni/ Pt
b) Lewis acids
c) CH3MgCl
d) HgCl2
Answer: d
Clarification: The catalyst used in the addition of iodine is HgCl2. Other catalyst that are mentioned cannot be used for this purpose.
2. Drying oils are used as the medium of paints and varnishes.
a) True
b) False
Answer: a
Clarification: Drying oils are used as the medium of paints and varnishes. When paints and varnishes are applied in thin layers, linseed oil quickly dries up to form a protective layer.
3. Which of the following is responsible for rancidity?
a) Alkalies
b) Ketones
c) Aldehydes
d) Alcohols
Answer: c
Clarification: Volatile acids and aldehydes are responsible for rancidity due to their offensive odour.
4. The number of milligrams of KOH required for the saponification of one gram of oil or fat is called ____________
a) Acid number
b) Iodine number
c) Richert-Meissl number
d) Saponification number
Answer: d
Clarification: The number of milligrams of KOH required for the saponification of one gram of oil or fat is called saponification number. The long chain fatty acids found in fats have a low saponification value because they have a relatively fewer number of carboxylic functional groups per unit mass of the fat as compared to short chain fatty acids.
5. Iodine number is defined as number of grams of iodine needed for the iodination of ________ gram/grams of oil or fat.
a) 1
b) 5
c) 100
d) 1000
Answer: c
Clarification: Iodine number is defined as number of grams of iodine needed for the iodination of 100 grams of oil or fat. Iodine numbers are often used to determine the amount of unsaturation in fatty acids. This unsaturation is in the form of double bonds, which react with iodine compounds. The higher the iodine number, the more C=C bonds are present in the fat.
6. Richert-Meissl number is defined as the volume of 0.1M KOH solution required for the neutralisation of _______ gram/grams of fat or oil.
a) 1
b) 5
c) 100
d) 1000
Answer: b
Clarification: Richert-Meissl number is defined as the volume of 0.1M KOH solution required for the neutralisation of 5grams of fat or oil. It is an indicator of how much volatile fatty acid can be extracted from fat through saponification.
7. Which of the following tells the amount of free fatty acids present in fat or oil?
a) Acid number
b) Iodine number
c) Saponification number
d) Richert-Meissl number
Answer: a
Clarification: Acid number tells the amount of free fatty acids present in fat or oil. It is the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of chemical substance.
8. Which of the following helps in the classification of oils into drying, semi-drying and non-drying categories?
a) Acid number
b) Iodine number
c) Saponification number
d) Richert-Meissl number
Answer: b
Clarification: Iodine number helps in the classification of oils into drying, semi-drying and non-drying categories. Iodine numbers are often used to determine the amount of unsaturation in fatty acids. This unsaturation is in the form of double bonds, which react with iodine compounds. The higher the iodine number, the more C=C bonds are present in the fat.
9. Which of the following is of special value in testing the purity of butter and desi-ghee?
a) Acid number
b) Iodine number
c) Saponification number
d) Richert-Meissl number
Answer: d
Clarification: Richert-Meissl number is of special value in testing the purity of butter and desi-ghee. It is an indicator of how much volatile fatty acid can be extracted from fat through saponification.
10. The smaller is the saponification value, the higher will be the molecular weight of oil or fat.
a) True
b) False
Answer: a
Clarification: The smaller is the saponification value, the higher will be the molecular weight of oil or fat. The long chain fatty acids found in fats have a low saponification value because they have a relatively fewer number of carboxylic functional groups per unit mass of the fat as compared to short chain fatty acids.
areas of Engineering Chemistry for Experienced people,