Revision: Carbon and Its Compounds Science SSLC (English Medium) Class 10 Tamil Nadu Board of Secondary Education

The process of the slow conversion of vegetable matter into carbon-rich substances is called carbonization.

Adsorption is the property due to which a substance absorbs gases, liquids and solids on its surface.

The property of self-linking of atoms of an element through covalent bonds in order to form straight chains, branched chains and cyclic chains of different sizes is known as catenation.

The characteristic of the carbon atom, by virtue of which it forms four covalent bonds, is called the tetravalency of carbon.

Carbon possesses a unique property of combining with other carbon atoms to form long chains. This property is called catenation. The chains can be straight, branched or closed.

The self-linking property of atoms of an element to form very long straight or branched chains and cyclic rings is known as catenation. This property is shown by carbon whose small size and tetravalency helps it to form large structures by self-linking.

Organic compounds are the compounds of carbon.

An atom or a group of atoms attached to an alkyl group, which takes part in most of the chemical reactions, is called a functional group or functional radical.

Compounds having the same molecular formula but different structural formulas are called isomers and the phenomenon is called isomerism.

When two or more compounds have a similar molecular formula but are different in the arrangement of carbon atoms in straight or branched chains, the compounds are referred to as chain isomers.

The hydrocarbons that have double or triple covalent bonds between two adjacent carbon atoms are called unsaturated hydrocarbons.

OR

The carbon compounds having a double bond or triple bond between two carbon atoms are called unsaturated compounds. Ethene and ethyne are unsaturated hydrocarbons.

The unsaturated hydrocarbons containing a carbon-carbon double bond are called ‘Alkenes’.

The unsaturated hydrocarbons whose structures contain a carbon-carbon triple bond are called ‘Alkynes’.

Saturated hydrocarbons (containing a single bond) are called ‘Alkanes’.

Hydrocarbons are compounds that 9re made up only of carbon and hydrogen atoms.

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The compounds which contain carbon and hydrogen as the only two elements are called hydrocarbons.

Saturated hydrocarbons are hydrocarbons in which the valencies of all atoms are satisfied by single bonds.

The compounds which contain carbon and hydrogen as the only two elements are called hydrocarbons.

"The hetero atoms or the groups of atoms containing hetero atoms are called functional groups."

A series of compounds with similar chemical properties, in which members differ from one another by an additional CH₂ group, is called a homologous series.

The same functional group substitutes for hydrogen in a carbon chain is called a homologous series.

OR

A homologous series is a group of organic compounds having  similar structure and similar chemical properties in which the successive compounds differ by a CH₂ group.

OR

The series of compounds formed by joining the same functional group in the place of a particular hydrogen atom on the chains having sequentially increasing length is called homologous series.

Nomenclature is the system of assignment of names to organic compounds.

C_nH_2n+1COOH (or RCOOH)

• Hydrocarbons contain only carbon and hydrogen atoms and are the basic type of organic compounds.
• Saturated hydrocarbons have single bonds (e.g. methane, ethane, propane).
• Unsaturated hydrocarbons have double or triple bonds (e.g. ethene, ethyne).
• To draw structures, join the carbon atoms first, then add hydrogen atoms to complete 4 bonds per carbon.
• Ethene has a double bond, and ethyne has a triple bond between carbon atoms.

• The IUPAC system provides a unique, systematic way to name carbon compounds based on structure, replacing confusing common names.
• An IUPAC name has three parts: prefix, parent, and suffix, reflecting the carbon chain and functional group.
• The parent name is based on the longest carbon chain, and its ending changes to –ane, –ene, or –yne depending on the number of bonds.
• Functional groups are shown as prefixes or suffixes, and the chain is numbered to give them the lowest possible number.
• If the suffix begins with a vowel, the final ‘e’ in the parent alkane name is dropped (e.g., propane → propanone).

• Ethanol is a colourless liquid with a boiling point of 78 °C, soluble in water, and used in medicines, drinks, and as a clean-burning fuel (e.g., gasohol).
• Ethanol reacts with sodium to form sodium ethoxide and hydrogen gas is evolved.
• When heated with concentrated H₂SO₄ at 170 °C, ethanol undergoes dehydration to form ethene, an unsaturated compound.
• Methanol is highly poisonous, and industrial ethanol is made unfit for drinking by mixing methanol and adding a blue dye (denatured spirit).

• Ethanoic acid (acetic acid) is a carboxylic acid; its 5–8% aqueous solution is vinegar, and it shows acidic nature by turning blue litmus red.
• Pure ethanoic acid freezes at 17 °C (290 K), so it is called glacial acetic acid.
• Being a weak acid, ethanoic acid is not completely ionised in aqueous solution.
• Ethanoic acid reacts with bases, carbonates, and bicarbonates to form a salt, water, and CO₂ (CO₂ turns lime water milky).
• It reacts with ethanol in the presence of conc. H₂SO₄ to form an ester (ethyl ethanoate) with a sweet smell (esterification).