Revision: Amazing World of Carbon Compounds Science and Technology 2 SSC (English Medium) 10th Standard Maharashtra State Board

The compounds of carbon having double or triple bonds between the carbon atoms are known as unsaturated carbon compounds.

The valencies of all the atoms are satisfied by single bonds between them. Such carbon compounds are called saturated compounds.

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

The compounds having this characteristic unit in their structure are called aromatic compounds.

• 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).

• Carbon compounds can have straight, branched, or ring chains of carbon atoms.
• Isomers have the same formula but different structures (e.g., butane).
• Crude oil is a mix of hydrocarbons; fuels like LPG and petrol are separated by fractional distillation.
• Saturated hydrocarbons have single bonds, while unsaturated ones have double or triple bonds.
• Aromatic compounds, such as benzene, have rings with alternating double bonds.

• 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).