Longest chain: 5 carbons (Pentane).
Substituents: Methyl group at position 2 and 4.
2.2,4-Dimethylpent-2-ene
Longest chain containing the double bond: 5 carbons.
Double bond starts at C2. Methyl groups at C2 and C4.
3.4-Methylpent-2-yne
Longest chain containing triple bond: 5 carbons (Pentyne).
Numbering from left gives triple bond lowest number (2). Methyl substituent at C4.
4.2-Bromo-3-chlorobutane
Longest chain: 4 carbons (Butane). Substituents: Bromo and Chloro.
Alphabetical order: Bromo comes before Chloro. Numbering starts from right to give lowest locants set
(2,3).
5.Pentan-2-one
5 Carbon chain ketone. Carbonyl group at position 2.
6.Methylcyclopentane
Cyclic ring of 5 carbons (Cyclopentane) with one methyl substituent.
7.Ethane-1,2-diol
Two carbon chain. Two -OH groups at positions 1 and 2. Suffix is 'diol'.
8.But-2-enal
4 Carbon chain with aldehyde group (C1). Double bond at C2. (Crotonaldehyde).
9.Phenol (or Benzenol)
-OH group attached directly to Benzene ring.
10.Methanoic Acid
Single carbon carboxylic acid. Common name: Formic Acid.
The unique ability of carbon atoms to form bonds with other atoms of carbon giving
rise to large molecules (chains, branches, rings) is called catenation. Carbon shows maximum catenation
due to its small size and strong C-C bond energy.
23.Micelle & Cleaning Action
Micelle: An aggregate of soap molecules where the hydrophobic tails cluster in the
center (trapping oil) and hydrophilic heads face outward towards water. Action: Soap molecules form micelles around dirt/oil particles. The hydrophobic tail
dissolves in oil, hydrophilic head in water. Agitation lifts the oil drop from the surface into water,
forming an emulsion that washes away.
24.Saturated vs Unsaturated
Saturated: Single bonds only (Alkanes). E.g., Ethane. Unsaturated: Double or triple bonds present (Alkenes/Alkynes). E.g., Ethene. Burns with
sooty flame.
Crown shaped ring structure. 8 Sulphur atoms linked in a ring.
27.Dehydration of Ethanol
$\text{CH}_3\text{CH}_2\text{OH} \xrightarrow{\text{Conc. H}_2\text{SO}_4, 443 K}
\text{CH}_2=\text{CH}_2 + \text{H}_2\text{O}$
Product: Ethene. Sulphuric acid acts as a dehydrating agent.
28.Scum Formation
Hard water contains Calcium and Magnesium salts. Soap reacts with these ions to
form insoluble precipitates called Scum (Calcium/Magnesium stearate), which hinders cleaning.
29.Detergents vs Soaps
Detergents are ammonium or sulphonate salts of long chain carboxylic acids. Their
charged ends do not form insoluble precipitates with Calcium and Magnesium ions in hard water, unlike
soaps. Hence they remain effective.
