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

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.

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

Key PointsAlkyl Group: An alkyl group is indeed formed when a hydrogen atom is removed from a carbon atom in a saturated hydrocarbon, typically by breaking a C-H bond.

CH₃ Molecule: When a hydrogen atom is removed from a CH₃ group, the result is the -CH₂ group, which is a common alkyl group. 

Alkyl Groups in Organic Molecules: Alkyl groups are derived by removing a hydrogen atom from saturated hydrocarbons, and they are fundamental components of organic molecules.

Important PointsSaturated Hydrocarbons: Saturated hydrocarbons are hydrocarbons in which all carbon atoms are connected by single bonds, and they are often referred to as alkanes.

Alkyl Group Function: Alkyl groups are important because they modify the chemical properties of larger organic molecules and can act as substituents in chemical reactions.

Additional InformationExamples of Alkyl Groups: Examples of alkyl groups include methyl (-CH₃), ethyl (-C₂H₅), propyl (-C₃H₇), etc., which are all derived from their respective hydrocarbons by removing a hydrogen atom.

Hydrocarbon Derivatives: The removal of a hydrogen atom from any saturated hydrocarbon results in the creation of an alkyl group, which can then form more complex molecules through bonding with other atoms or groups.

Concept:

The acidity of compounds:

• The acidity of compounds is determined by their ability to donate hydrogen ions in solution.
• The greater the ease of donation or liberation of the hydrogen ions, the stronger is the acid.
• The acidic proton of the compound is generally attached to an electronegative atom.
• The strength of the acidity is greatly influenced by the substituents or groups attached.
• The strength of an acid is measured by its pKa value. Lower the pKa, stronger is the acid.

Factors influencing the acid strength-

• Inorganic acids are much stronger than Organic acids.
• The stability of the conjugate base-
  • if the negative charge is resonance stabilized in the conjugate base, then the compound is more acidic compared to the compound whose conjugate base has the charge localized.
• Electronegative substituents or groups like F, Cl, Br, I increase the acidity via inductive electron withdrawal (-I).
• Electron donating groups such as - OR, -Me, etc. decrease the acidity via the +R and +I effect.
• Electron withdrawing groups such as NO2,-CF3, -COOH, -CN increases the acidity via the –R effect.
• Hydrogen attached to sp2 Carbon is more acidic than hydrogen attached to sp3 carbon.
• The acidity order is sp> sp2>sp3.

Explanation:

• The substituents acting and the acidity order of the compounds are as given below:

Molecule	Effect of substituients	Acidic nature
	Benzoic acid is acidic in nature as the conjugate base is resonance stabilized.	More acidic than p-methyl benzoic acid.
	Methyl group has electron releasing +I effect which decreases its acidity.	Least acidic
	Chlorine exerts -I and +R effect which increases its acidity.	More acidic than benzoic acid.
	-NO2 exerts a strong -R effect so the acidity gets increased.	Most acidic

• From the above table, its is clear that p nitro benzoic acid is the most acidic in nature.
• This is because resonance effect is stronger than the Inductive effect which operates in p-nitro benzoic acid.

​is thus the most acidic in nature.

• 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.

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:

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.

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.

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.

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.