NCERT Notes: Grade 10 Science - Chapter 4: Carbon and Its Compounds

Introduction

Carbon, a non-metal, sits at the center of life on Earth. Its unique ability to form bonds with other carbon atoms, as well as with atoms of different elements, leads to a vast array of compounds with diverse properties.

The Versatile Carbon Atom

Tetravalency of Carbon: With four valence electrons, carbon can form four covalent bonds. This tetravalency allows it to create large complex structures.

Catenation: Carbon’s ability to bond with itself, forming chains and rings, is called catenation. This leads to the vast diversity in carbon compounds.

Hydrocarbons

Compounds made entirely of carbon and hydrogen are called hydrocarbons. They are mainly of three types:

1. Alkanes: Saturated hydrocarbons with single bonds. Eg: Methane (CH₄).
2. Alkenes: Unsaturated hydrocarbons with double bonds. Eg: Ethene (C₂H₄).
3. Alkynes: Unsaturated hydrocarbons with triple bonds. Eg: Ethyne (C₂H₂).

Functional Groups

Atoms or group of atoms replacing hydrogen in hydrocarbons determine the properties and nature of organic compounds. Examples include:

1. Alcohol: -OH group
2. Aldehyde: -CHO group
3. Carboxylic Acid: -COOH group

Homologous Series

A series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called a homologous series. They have:

1. A common general formula.
2. Consecutive members differing by a -CH₂ unit.
3. Gradually changing physical properties.

Chemical Properties of Carbon Compounds

1. Combustion: Carbon compounds burn in the presence of oxygen to release energy.
2. Oxidation: Alcohols can be oxidized to form acids.
3. Addition Reaction: Unsaturated carbon compounds can add halogens, hydrogen, etc., across double/triple bonds.
4. Substitution Reaction: In saturated hydrocarbons, a hydrogen atom can be replaced by other atoms/groups.

Ethanol and Ethanoic Acid

Ethanol (C₂H₅OH):

• Obtained from sugars through fermentation.
• Used in beverages, medicines, and as a fuel in spirit lamps.

Ethanoic Acid (CH₃COOH):

• Vinegar’s main component.
• It reacts with bases to give salts and with carbonates/bicarbonates to release carbon dioxide.

Soaps and Detergents

Saponification: The process of making soap by the hydrolysis of fats and oils with alkalis. Soaps are sodium or potassium salts of long-chain fatty acids.

Detergents: These are cleansing agents with a similar action as soaps but are effective in hard water. They are sulfonate or sulfate salts.

Conclusion

The vast domain of carbon compounds, from the simplicity of methane to the complexity of DNA, showcases carbon’s significance in the world of chemistry. Its tetravalency and catenation ability drive the myriad of organic reactions, forming the basis for life and industrial applications.

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Reference: NCERT Grade 10 Science - Chapter 4: Carbon and Its Compounds

Note: This article is a summary and interpretation of Chapter 4 from the Science NCERT textbook for Grade 10. For a thorough understanding, students should refer to the original NCERT textbook.