Carbon and Its Compounds

Class 10 Science • Chapter 04 (Deep Detail)

1. Why Covalent Bonds?

Carbon (2,4) uses Tetravalency and Catenation forming covalent bonds.

Diamond: 1 Carbon bonded to 4 others (Tetrahedral). Rigorous 3D structure. NO free electrons $\to$ Insulator.
Graphite: 1 Carbon bonded to 3 others (Hexagonal Layers). One free electron $\to$ Good Conductor. Layers slide $\to$ Slippery.
Fullerene (C-60): Football shape, 60 Carbons arrange in Pentagons and Hexagons.

2. Hydrocarbons (Saturated/Unsaturated)

Saturated (Alkanes): Single bond. $C_nH_{2n+2}$. (Methane, Ethane).

Unsaturated: Double (Alkenes $C_nH_{2n}$) or Triple (Alkynes $C_nH_{2n-2}$).

CYCLIC COMPOUNDS

Cyclohexane ($C_6H_{12}$): Saturated Ring. Each C has 2 H.
Benzene ($C_6H_6$): Unsaturated Ring. Alternating Double Bonds. Each C has 1 H.

IUPAC NAMING Format: Prefix + Word Root + Suffix
1C: Meth, 2C: Eth, 3C: Prop, 4C: But, 5C: Pent.
Groups:

Alcohol (-OH) $\to$ -ol
Aldehyde (-CHO) $\to$ -al
Ketone (-CO-) $\to$ -one
Carboxylic (-COOH) $\to$ -oic acid
Double Bond (=) $\to$ -ene
Triple Bond ($\equiv$) $\to$ -yne

Example: $CH_3-CH_2-OH$ $\to$ Eth + an + ol = Ethanol.

3. Chemical Properties

Combustion: $CH_4 + 2O_2 \to CO_2 + 2H_2O + Heat$. (Blue flame if saturated, Yellow/Sooty if unsaturated).
Oxidation: Alcohol $\to$ Acid. $$ CH_3CH_2OH \xrightarrow{Alk. KMnO_4} CH_3COOH $$
Addition (Hydrogenation): Veg Oil (Unsat) + $H_2 \xrightarrow{Ni} $ Veg Ghee (Sat).
Substitution: $CH_4 + Cl_2 \xrightarrow{Sunlight} CH_3Cl + HCl$.

4. Important Compounds

Ethanol ($C_2H_5OH$)

Reaction with Na: $2Na + 2C_2H_5OH \to 2C_2H_5ONa \text{ (Sod. Ethoxide)} + H_2$.
Dehydration: $C_2H_5OH \xrightarrow{Conc. H_2SO_4, 443K} C_2H_4 \text{ (Ethene)} + H_2O$.

Ethanoic Acid ($CH_3COOH$)

Esterification: Acid + Alcohol $\to$ Ester (Sweet Smell).
$CH_3COOH + C_2H_5OH \xrightarrow{H^+} CH_3COOC_2H_5 + H_2O$.
Saponification: Ester + Base $\to$ Soap + Alcohol.
$CH_3COOC_2H_5 + NaOH \to C_2H_5OH + CH_3COONa \text{ (Soap)}$.

5. Soaps and Detergents

Soap: Sodium salt of fatty acid. Long Carbon Tail (Hydrophobic/Dirt-loving) + Ionic Head (Hydrophilic/Water-loving).
Forms Micelles to trap dirt.
Scum: In hard water (Ca/Mg ions), soap fails and forms scum.

Detergents: Ammonium/Sulphonate salts. Work well in Hard Water. NO Scum.

[IMAGE PLACEHOLDER: MICELLE FORMATION]

Diagram of a Micelle. 1. Show single soap molecule (Zig-zag tail, Circular Head). Label Head "Hydrophilic", Tail "Hydrophobic". 2. Show spherical Micelle containing an Oil Droplet in the center. All Tails pointing inwards into oil. All Heads pointing outwards interactions with water.

EXAM TRICK: ISOMERS Pentane ($C_5H_{12}$): 3 Isomers. 1. n-pentane (Straight). 2. iso-pentane (CH3 branch on 2nd C). 3. neo-pentane (Central C surrounded by 4 Cs).