Maharashtra State Board · Class 10 · Chemistry · Chapter 9

Carbon and Its Compounds — Formula Sheet

Board Formulas

11 formulas

1.General Formula of Alkanes★
$C_{n} H_{2 n + 2}$
$n$ : Number of carbon atoms (n = 1, 2, 3, ...)
Saturated hydrocarbons — only single C-C bonds. Methane, ethane, propane, butane.
2.General Formula of Alkenes★
$C_{n} H_{2 n}$
One C=C double bond. Ethene (C_2H_4), propene, but-1-ene.
3.General Formula of Alkynes
$C_{n} H_{2 n - 2}$
One C≡C triple bond. Ethyne (acetylene, C_2H_2).
4.Combustion of Methane
$C H_{4} + 2 O_{2} \to C O_{2} + 2 H_{2} O + heat$
Complete combustion gives CO_2 and water; a blue flame indicates enough O_2.
5.General Combustion of Alkane
$C_{n} H_{2 n + 2} + (\frac{3 n + 1}{2}) O_{2} \to n C O_{2} + (n + 1) H_{2} O$
Substitute n to get the equation for methane, ethane, etc.
6.Addition (Hydrogenation)★
$C H_{2} = C H_{2} + H_{2} Ni C H_{3} - C H_{3}$
Ni catalyst adds H_2 across double bond — converts unsaturated to saturated. Basis of vanaspati manufacture.
7.Substitution (Chlorination of Methane)
$C H_{4} + C l_{2} sunlight C H_{3} C l + H C l$
One H replaced by Cl. Free-radical substitution — characteristic of alkanes.
8.Oxidation of Ethanol to Ethanoic Acid
$C H_{3} C H_{2} O H alk. KMnO_{4} Δ C H_{3} C O O H$
Alkaline KMnO_4 or acidified K_2Cr_2O_7 oxidises the -OH to -COOH.
9.Ester Formation (Esterification)★
$C H_{3} C O O H + C H_{3} C H_{2} O H conc. H_{2} SO_{4} C H_{3} C O O C_{2} H_{5} + H_{2} O$
Sweet-smelling ester — used in perfumes and flavours. Acid catalyst is conc. H_2SO_4.
10.Saponification (Soap Making)
$Fat/Oil + 3 N a O H \to Soap + Glycerol$
Alkaline hydrolysis of triester. Sodium salt of long-chain fatty acid = soap.
11.Reaction of Sodium with Ethanol
$2 C H_{3} C H_{2} O H + 2 N a \to 2 C H_{3} C H_{2} O N a + H_{2} ↑$
Distinguishes -OH group from ether — produces H_2 gas.