Organic Chemistry MCQ Quiz - Objective Question with Answer for Organic Chemistry - Download Free PDF

Concept:

Fibre can be obtained from various sources.

Natural Fibre: Natural fibres are the fibres that are obtained from plants, animals or mineral sources. Some examples are cotton, silk, wool etc.

Synthetic fibres: Synthetic fibres are man-made polymers designed to make a fabric. Polymers are obtained when many small units are joined together chemically. Some examples are silk, acrylic, rayon, dacron etc.

Conclusion:

• Silk, cotton and jute are natural fibres.
• Acrylic is not a natural fibre, it is a man-made synthetic fibre.

Rayon:

• Rayon is a synthetic fibre whose properties are similar to that of silk.
• Rayon is obtained from a natural source like wood pulp. Hence this is the correct option.
• It has a very shiny appearance and hence called artificial silk.

Additional Information

• Nylon was the first 'fully synthetic' fibre that was developed in the 1930s by an American researcher, Wallace Carothers at Du Pont, a chemical firm. 
• It was made without using any natural raw materials. It was prepared from coal, water and air.
• Nylon is a family of linear polymers which contains amide groups in the backbone of the chain.
• Nylon 6, Nylon 6, 6, are different nylon polymers.
• Nylon 6, 6- It is produced by the polymerisation of hexamethylenediamine and adipic acid.
• Nylon 6 - It is produced by the polymerisation of caprolactam. 

Properties of Nylon

• It is very strong and elastic
• Nylon fibres have high toughness and abrasion resistance.
• Easy to wash.

Uses

• ​Clothing - Shirts, raincoats, swimwear.
• For making bristles of brushes.
• Used for making fishing nets.
• In the automobile industry.

The correct answer is Iodine.

Key Points

• Antiseptics are chemicals that either kill or prevent the growth of microorganisms in or on living tissue.
• Antiseptics are applied to living tissues such as wounds, cuts, ulcers, and diseased skin surfaces.
• Iodine, chlorhexidine, alcohol, acetate, hydrogen peroxide, boric acid, silver nitrate, silver sulfadiazine, and sodium hypochlorite are among the most commonly used wound treatments today.
• Iodine is a powerful antiseptic. Its 2-3 percent solution in the alcohol-water mixture is known as a tincture of iodine. It is applied to wounds

Thus, iodine can be put on wounds as an antiseptic.

The correct answer is Polyblend.

Key Points

• Polyblend is a fine powder obtained by recycling and modifying plastics.
• It is used in various applications, such as making roads by mixing it with bitumen to enhance road durability.
• The process of creating polyblend involves shredding and melting waste plastics, followed by converting them into a powder form.
• Polyblend has been recognized as a practical solution for managing plastic waste and reducing environmental pollution.
• Its usage in road construction increases the longevity of roads by making them water-resistant and more resilient to weather changes.

Additional Information

• Polystyrene: A synthetic polymer used to manufacture products like packaging, insulation, and disposable cups.
• Polythene: A lightweight, durable plastic commonly used in packaging materials like bags and films.
• Polyethylene: A widely-used polymer, often found in bottles, containers, and plastic wraps.
• Plastic Recycling: The process of converting waste plastic into reusable materials to reduce environmental harm.
• Environmental Benefits: Using recycled plastic like polyblend in infrastructure helps decrease plastic waste accumulation, lowers pollution, and promotes sustainable development.

Key PointsPVC (Polyvinyl chloride):

• Application: Manufacture of pipes, plastic furniture, coating of electric conductors, etc.
• Additional Info: PVC is one of the most widely used synthetic plastics. It can be made rigid (for pipes and doors) or flexible (for electrical insulation).
• Common Use: Construction (pipes), healthcare (medical tubing), electrical (cables), and packaging (films).

Polythene (Polyethylene):

• Application: Used in the manufacture of carry bags, tarpaulin sheets, and plastic containers.
• Additional Info: There are different types of polyethylene, such as low-density polyethylene (LDPE) and high-density polyethylene (HDPE), each used for different purposes.
• Common Use: Packaging (plastic bags, films), toys, containers, and more.

Natural Rubber:

• Application: Primarily used in the manufacture of tyres and various other rubber products.
• Additional Info: Derived from the latex of rubber trees, natural rubber is used in manufacturing items that require elasticity and durability.
• Common Use: Tyres, footwear, seals, gaskets, and medical products.

Teflon (Polytetrafluoroethylene - PTFE):

• Application: Most commonly used for coating of the inner surface of non-stick cookware.
• Additional Info: Teflon is known for its non-stick properties, electrical insulation, and resistance to heat and chemicals.
• Common Use: Non-stick cookware, pipe linings, electrical insulation, and lubricants.

Important Points

• PVC is one of the most versatile polymers, used in a variety of applications due to its durability, cost-effectiveness, and ease of manufacturing.
• Polythene is primarily used for packaging materials like bags, films, and containers due to its strength and moisture resistance.
• Natural rubber is key to the automotive industry, particularly in the production of tyres, due to its high elasticity and strength.
• Teflon is widely recognized for its use in non-stick cookware, but it is also used in many industrial applications such as cable insulation and gaskets because of its chemical and heat resistance.

Additional Information

• PVC: In addition to being used for plumbing and electrical insulation, it is also used in medical devices, such as blood bags and tubing, because of its ability to be sterilized.
• Polythene: HDPE is used for strong, impact-resistant applications such as storage tanks, while LDPE is used for flexible, low-density applications like plastic bags and wraps.
• Natural Rubber: Synthetic rubber, made from petroleum-based sources, is an alternative to natural rubber. However, natural rubber is still preferred in many high-performance applications, such as in tyres and seals.
• Teflon: Teflon’s ability to resist chemical corrosion makes it suitable for use in chemical processing industries, as well as for medical devices like catheters and surgical implants.

Answer:
Correct Answer: 3) I, II and III

Key Points-OH Group and Methanol: The -OH (hydroxyl) group in the carbon chain indeed influences the characteristic properties of methanol, such as its solubility in water and its ability to form hydrogen bonds.

Alcohols: Aliphatic hydrocarbons with an -OH group are classified as alcohols, a group of organic compounds that include methanol, ethanol, etc.

IUPAC Nomenclature: According to IUPAC rules, alcohols are named by replacing the 'e' in the alkane name with 'ol'. For example, methane becomes methanol, and ethane becomes ethanol.

Important PointsFunctional Group: The -OH group is the functional group in alcohols, and its presence makes alcohols different from alkanes and other hydrocarbons.

Naming Alcohols: The IUPAC naming system helps standardize the names of organic compounds, making it easier to identify the structure and class of the compound.

Additional InformationProperties of Alcohols: Alcohols are generally polar due to the hydroxyl group, and they often have higher boiling points than hydrocarbons due to hydrogen bonding.

Alcohol Applications: Alcohols, particularly methanol and ethanol, are used as solvents, fuels, and in chemical manufacturing.

• According to the law of Dobereiner’s triads, the atomic mass of the middle element of the triad is the arithmetic mean of the atomic masses of the other two elements.
• If A, B, and C are elements in Dobereiner’s triads, then the atomic mass of B will be equal to the arithmetic mean of the atomic mass of A and C.

Element	A	C	B = (A + C)/2
Atomic mass	40	137	= (40 + 137)/2 ≈ 88
Atomic Number	20	56	38
Element	Calcium	Barium	Strontium

 

Therefore, the atomic mass of element B is 88.

The correct answer is Nitrogen.

Important Points

​Amines:

• An amine is a functional group with a nitrogen atom having a lone pair.
• Basically, Amines are derived from ammonia (NH₃).
• Nitrogen has a valency of 5, that's why it makes a trivalent with a lone pair.

Uses:

• ​ Amines are used in water purification, medicine manufacturing, and insecticides, and pesticides.
• These are also used in the production of Amino acids.
• It is also used in pain-relieving medicines. 

Types:

• Amines are generally of four types:

1. Primary Amines
2. Secondary Amines
3. Tertiary Amines
4. Cyclic Amines

• Amines can be obtained from Halogen alkanes.

Biogas is produced from biomass by Anaerobic fermentation.

• The element carbon is available abundantly in nature and occurs in free as well as in the combined state.
• Carbon in Free State is found as diamond and graphite.
• In the Combined State, it is found in the following compounds:

 

In the form of Carbonates	Calcium Carbonate, Marble, Calamine(ZnCO3)
Fossil Fuel	Coal, Petroleum, Natural Gas
Carbonaceous Nutrients	Carbohydrates, Proteins, Fats
Natural Fibres	Cotton, Wool, Silk

The correct answer is Sodium benzoate.

Key PointsSodium benzoate is the sodium compound most commonly used as a preservative in items such as sauces, salad dressings, and beverages. Its excellent antimicrobial characteristics help extend the shelf life of foods and beverages.

 Additional Information

• Sodium bicarbonate - Commonly known as baking soda, is primarily used in baking as a leavening agent.
• Sodium fluoride - It's widely used in toothpaste and drinking water to prevent tooth decay.
• Sodium hypochlorite - This is the active ingredient in bleach and is commonly used for disinfection and water treatment.

The correct answer is Rayon

• Rayon is obtained from the wood pulp.
• Rayon is a regenerated cellulose fiber.
• It is made from natural sources such as wood and agricultural products.
• There are two types of man-made fibers.
  • Synthetic fibers: Synthetic fibers are made only from polymers found in natural gas and the by-products of petroleum. Examples: Nylon, Acrylics, Polyurethane, and Polypropylene
  • Regenerated fibers: Regenerated fibers are made from cellulose polymers that occur naturally in plants such as cotton, wool, hemp, and flax.  Examples: Rayon and Acetate.

Methane is the lightest hydrocarbon having one carbon and four hydrogen atoms. Its molecular weight is 16. It is also a fuel gas commonly called marsh gas because it is produced from marshy lands. Some facts about it: 

• Methane is produced when vegetation decomposes naturally within some geographical marshes, swamps.
• The main process behind the production of methane is anaerobic digestion.
• Biogas or Gobar gas also contains 60-70% of methane. 
• Methane is one of the greenhouse gases. Other greenhouse gases are- carbon dioxide, water vapour, nitrous oxide and ozone.
• Methane is produced in the soil during microbial decomposition of organic matter and reduction of CO2 under strictly anaerobic conditions. 

Hence, we conclude that Methane is known as Marsh gas.

Concept:

The compounds having a triple bond between carbon atoms are called Alkynes.

General Formula for various hydrocarbons groups are:

Alkane: C_nH_{2n + 2}

Alkene: C_nH_2n

Alkyne: C_nH_{2n - 2}

Application:

C₃H₄ follows the general formula for a compound for n = 3

Hence C₃H₄  belongs to the alkyne family.

The correct answer is Lexan.Key Points

• Lexan is a type of polycarbonate i.e., thermosetting polymers composed of carbonate groups. They are hard and are observably .
• They are strong, tough materials, and are optically . This is why a laminated polycarbonate (Lexan) is used to make bulletproof glass.

Important Points

• Kevlar is a heat-resistant and strong synthetic fiber.
• Usage of other polymers:

• Propanal is an example of an aldehyde  functional group.
• R−CHO is a general structural formula for Aldehyde.

Compound	Functional Group	Chemical Formula
Propanal	Aldehyde	CH3CH2-CHO
Propanol	Alcohol	CH3CH2CH2-OH
Propanone	Ketone	(CH3)2CO