CBSE · Class 10 · Chemistry · Chapter 4

Carbon and its Compounds — Formula Sheet

Board Formulas

10 formulas

1.General Formula of Alkane★
$C_{n} H_{2 n + 2}$
Saturated hydrocarbons; all C-C single bonds. Example: methane CH₄, ethane C₂H₆.
2.General Formula of Alkene
$C_{n} H_{2 n}$
Unsaturated; ONE C=C double bond. Example: ethene (ethylene) C₂H₄.
3.General Formula of Alkyne
$C_{n} H_{2 n - 2}$
Unsaturated; ONE C≡C triple bond. Example: ethyne (acetylene) C₂H₂.
4.Combustion of Ethanol
$C_{2} H_{5} O H + 3 O_{2} ⟶ 2 C O_{2} + 3 H_{2} O + heat$
Highly exothermic. Ethanol used as clean fuel additive (petrol + 10 % ethanol).
5.Dehydration of Ethanol★
$C_{2} H_{5} O H conc. H_{2} S O_{4}, 17 0^{\circ} C C_{2} H_{4} + H_{2} O$
Conc. H₂SO₄ is a dehydrating agent — removes H₂O and gives ethene.
6.Oxidation of Ethanol
$C_{2} H_{5} O H alk. K M n O_{4} /Δ C H_{3} C O O H$
Purple KMnO₄ → colourless — a common test. Also happens naturally when wine turns to vinegar.
7.Esterification★
$C H_{3} C O O H + C_{2} H_{5} O H conc. H_{2} S O_{4} C H_{3} C O O C_{2} H_{5} + H_{2} O$
Carboxylic acid + alcohol → sweet-smelling ester. Reversible; conc. H₂SO₄ acts as catalyst.
8.Ester + NaOH (Saponification)
$C H_{3} C O O C_{2} H_{5} + N a O H ⟶ C H_{3} C O O N a + C_{2} H_{5} O H$
'Saponification' = soap-making. Ester + alkali → soap + alcohol.
9.Ethanoic Acid + Sodium Bicarbonate
$C H_{3} C O O H + N a H C O_{3} ⟶ C H_{3} C O O N a + H_{2} O + C O_{2} (g)$
Effervescence of CO₂ turns lime water milky — confirms carboxylic acid group.
10.Soap (Long Chain Sodium Salt)
$C_{17} H_{35} C O O N a$
Sodium stearate — a typical soap. Hydrophobic C₁₇H₃₅ tail (dissolves grease) + hydrophilic COO⁻Na⁺ head (dissolves in water).