Railway Science (Chemistry-Organic Chemistry) (Part-II)

Total Questions: 50

1. Which type of sugar is responsible for sweetening in fruits? [RRB NTPC CBT - I (17/01/2021) Morning]

Correct Answer: (c) Fructose
Solution:

Fructose (C₆H₁₂O₆): Comes under the category of Monosaccharides (General Formula - Cₙ(H₂O)ₙ). Disaccharides - Sugar formed by linkage of two Monosaccharides.
Example: Lactose - Found in milk. Maltose - Germinating grains and vegetables. Sucrose - Also known as Table Sugar, Found in sugarcane. All Disaccharides have a formula - C₁₂H₂₂O₁₁.

2. Which of the following is an ester [RRB NTPC CBT - I (21/01/2021) Evening]

Correct Answer: (c) CH₃COOC₂H₅
Solution:

(Ethyl acetate). It is formed by the reaction of acetic acid (CH₃COOH) and ethanol (C₂H₅OH). The main use of esters is for flavorings and perfumes, however, they can also be used in the chemicals industry as solvents. Acetaldehyde {Ethanal (CH₃CHO)}. CH₃COOH (Acetic Acid), CH₃COCH(CH₃)₂ (3-Methyl-2-butanone).

3. Name the gas which is filled in wick-type lighters. [RRB NTPC CBT - I (28/01/2021) Evening]

Correct Answer: (a) Butane
Solution:

A hydrocarbon and a highly flammable, colorless, odorless, easily liquefied gas. Uses: Fuel for cigarette lighters and portable stoves, a propellant in aerosols, heating fuel, a refrigerant and in the manufacture of a wide range of products.

4. What is the IUPAC name of glycerol? [RRB NTPC CBT - I (16/02/2021) Morning]

Correct Answer: (d) Propane-1,2,3 -triol
Solution:

Glycerin is a type of carbohydrate called a sugar alcohol, or polyol. Some other IUPAC names:- Ethylene Glycol (Ethane-1,2 diol), Isopropyl alcohol (Propan-2-ol), Propanol or n-propyl alcohol (Propan -1-ol), Isobutanol (2-Methylpropan-1-ol).
IUPAC (International Union of Pure and Applied Chemistry) - An international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. Formation - 1919. Headquarters - North Carolina (United States).

5. Power Alcohol is a mixture of __________ and ethyl alcohol. [RRB NTPC CBT - I (22/02/2021) Morning]

Correct Answer: (d) Petrol
Solution:

Power alcohol (Ethyl alcohol) - Ethanol in the presence of a small quantity of benzene, mixed with petrol (80% petrol + 20% ethanol + small quantity of benzene). The octane Number is a measure of the quality of petrol. Benzene is a chemical that is a colorless or light yellow liquid at room temperature.

6. Ethanol is formed during: [RRB NTPC CBT - I (11/03/2021) Morning]

Correct Answer: (d) anaerobic respiration in yeasts
Solution:

Yeasts are single-celled organisms. They respire anaerobically and during this process yield alcohol. They are, therefore, used to make wine and beer. In Humans, The partial breakdown of glucose produces lactic acid (when there is a temporary deficiency of oxygen).

7. Formaldehyde is used in which of the following options? [RRB NTPC CBT - I (31/07/2021) Evening]

Correct Answer: (b) Perfumes
Solution:

Perfumes. Formaldehyde :- Formula: CH₂O, IUPAC name : Methanal, Properties :- Colourless, flammable, strong-smelling chemical. Uses :- Used in the production of fertilizer, paper, plywood, in household products, such as antiseptics, medicines, and cosmetics.

8. Functional group –CHO is present in which of the following? [RRB JE 22/05/2019 (Evening)]

Correct Answer: (a) Aldehyde
Solution:

Any of a class of organic compounds in which a carbon atom shares a double bond with an oxygen atom, a single bond with a hydrogen atom, and a single bond with another atom or group of atoms.
A Ketone is an organic compound in which the carbonyl group is attached to a carbon atom within the carbon chain. Functional group - RCOR (R is hydrocarbon). Alcohol - The functional group is the hydroxyl group, –OH. Carboxyl group - A hydroxyl group bonded to carbonyl group, –COOH.

9. Which of the following is a byproduct of soap? [RRB JE 23/05/2019 (Morning)]

Correct Answer: (d) Glycerin
Solution:

It is a natural ingredient derived from vegetable oils or animal fats. It is a clear, transparent, colorless, odorless liquid. Isoprene (C₅H₈) is a hydrocarbon compound that is produced by plants and animals and is used in the production of synthetic rubber.
Ethylene glycol (C₂H₆O₂) is a synthetic liquid substance that absorbs water. It is odorless, but has a sweet taste. It is used as antifreeze liquid in cooling and heating systems. Butene (C₄H₈) is an organic compound and is used for the production of a wide variety of chemicals in the gasoline and rubber processing areas.

10. Soaps are sodium or potassium salts of long chain- [RRB JE 23/05/2019 (Afternoon)]

Correct Answer: (d) Carboxylic acid
Solution:

Soaps are formed by the process of saponification. Chemical formula of soap - C₁₇H₃₅COO plus a metal cation either Sodium (Na⁺ ) or Potassium (K⁺ ). Carboxylic acids - Organic compounds in which a carbon (C) atom is bonded to an oxygen (O) atom by a double bond and to a hydroxyl group (―OH) by a single bond.
General formula : R-COOH. Aldehydes - The carbonyl group (C=O) is bonded to carbon and hydrogen. General formula : R-CHO. Alcohols - Organic compounds with at least one hydroxyl group (―OH) bound to saturated carbon atom. General formula : CₙH₂ₙ₊₁OH.