Welcome to Class 10 Chemistry – Chapter 11: Organic Chemistry Notes! This chapter focuses on carbon compounds, their types, sources, uses, and important reactions. You will learn about alkanes, alkyl radicals, and functional groups, which form the foundation of organic chemistry.
The PDF notes for this chapter include MCQs, short questions, and detailed long questions, making it a complete resource for exam preparation. With these notes, you can revise formulas, reactions, and important diagrams all in one place, ensuring you are fully prepared for your exams.
Important MCQs – Chapter 11 Organic Chemistry
1. Originally, the term “organic chemistry” referred to the study of compounds obtained from:
(a) Minerals
(b) Water
(c) Living organisms ✅
(d) Gases
2. According to the Vital Force Theory, organic compounds could only be produced:
(a) From synthetic chemicals
(b) In the presence of sunlight
(c) By living organisms only ✅
(d) Inside laboratories
3. Which type of bonding is commonly found in organic compounds?
(a) Ionic bonding
(b) Metallic bonding
(c) Covalent bonding ✅
(d) Coordinate bonding
4. Which two main groups of organic compounds are synthesized by animals?
(a) Carbohydrates and vitamins
(b) Proteins and fats ✅
(c) Oils and cellulose
(d) Gums and rubber
5. What are coal, petroleum, and natural gas collectively called?
(a) Natural elements
(b) Renewable fuels
(c) Fossil fuels ✅
(d) Organic rocks
Short Questions – Chapter 11 Organic Chemistry
1. What is the importance of natural gas?
Answer: Natural gas is an important source of energy and is used as a domestic fuel (e.g., CNG, LPG), an industrial fuel, and as a source of hydrogen gas and fertilizers. It is a clean and efficient source of energy, making it widely used in homes, industries, and agriculture.
2. Define functional group with an example.
Answer: A functional group is an atom or a group of atoms that determines the chemical properties of an organic compound. For example, in alcohols, the –OH group is the functional group. Example: CH₃–OH (methyl alcohol).
3. Define structural formula. Draw the structural formulae of n-butane and isobutane.
Answer: A structural formula shows the arrangement of atoms in a molecule.
-
n-Butane: CH₃–CH₂–CH₂–CH₃
-
Isobutane: (CH₃)₂CH–CH₃
Explanation: The structural formula helps to visualize how atoms are connected, unlike the molecular formula, which only shows the number of atoms.
Long Questions – Chapter 11 Organic Chemistry
Question: What are amines? Explain the different types of amines giving an example of each type. How is the primary amino group identified?
Answer: Amines are organic compounds derived from ammonia (NH₃) by replacing one or more hydrogen atoms with alkyl (R) or aryl (Ar) groups. They contain a nitrogen atom with a lone pair, are basic in nature, and are widely used in dyes, drugs, plastics, and fertilizers.
Amines are classified based on how many hydrogen atoms in ammonia are replaced:
-
Primary (1°) Amines: One hydrogen atom is replaced by an alkyl or aryl group. Formula: R–NH₂.
Examples: Methylamine (CH₃–NH₂), Aniline (C₆H₅–NH₂) -
Secondary (2°) Amines: Two hydrogen atoms are replaced by two alkyl or aryl groups. Formula: R₂–NH.
Examples: Dimethylamine (CH₃–NH–CH₃), Diphenylamine (C₆H₅–NH–C₆H₅) -
Tertiary (3°) Amines: All three hydrogen atoms are replaced by alkyl or aryl groups. Formula: R₃–N.
Examples: Trimethylamine ((CH₃)₃N), Triphenylamine ((C₆H₅)₃N)
Identification of Primary Amino Group (–NH₂):
The Carbylamine Test (Isocyanide Test) is used to specifically identify primary amines. In this test, a primary amine reacts with chloroform and alcoholic KOH to produce isocyanide, which has a foul pungent smell.
Reaction:
R–NH₂ + CHCl₃ + 3KOH → R–NC + 3KCl + 3H₂O
Observation: The production of a foul-smelling isocyanide confirms the presence of a primary amino group.
Download PDF
You Can download the complete chapter notes in PDF format for detailed study and revision.
English Medium View English Medium
Urdu Medium View Urdu Medium PDF