Substitution Reactions One atom in a compound is replaced by another atom or
group of atom
Addition Reactions:- Unsaturated hydrocarbons, (double bond/triple bond ) react with other molecules (H2, C12,HC1, HBr etc) to form saturated hydrocarbons.
Polymerisation:- Monomers combines to form polymers. nCH2 = CH2 — CH2 – CH2]-n
Combustion of hydrocarbons: – Hydrocarbon combines with oxygen to form C02 and H20
CH4 + 202 —* C02 + 2H20 + Heat
methane.
Thermal cracking:- Some hydro carbons with high molecular masses, when heated in the absence of air undergo decomposition to form hydrocarbons with lower molecular
Eg: CH3 – CH2 – CH3(C3H8H CH2 = CH2 4- CH4
Propane Ethene Methane
Alcohols
Functional group : – OH (Hydroxy)
Metahnol
Molecualr formula CH3OH
Uses:
Solvent in the manufacture of paints
Manufacture of varnish and formalin
Industrial Preparation
High pressure and temperature
CO + 2H2 > CH3 – OH
Etahnol
Molecular formula : CH3 – CH2 – OH
Uses
Fuel
Beverage
Preservative
Solvent for medicine
Industrial Preparation
By the fermentation of dilute molasses in presence of yeast. Invertase
C12H22O11 + H2O * C6H12O6 + C6H12O6
C6Hi2O6 ZymaSe > 2C2H5OH + 2CO2
Ethanoic acid
Molecular formula : CH3 – COOH
Industrial preparation : Catalyst
CH3 — OH + CO > CH3 — COOH
Methanol
Uses:
In manufacture of rayon
In rubber and silk industry
Esters
Alcohol + Carboxylic acid Ester + Water
Functional group : -COOR
Soap
Fatty acids combine with glycerol to form oil or fats. Soap is the salt formed when oils and fats react with alkalies like sodium hydroxide, potassium hydroxide.
Soap dosen’t lather well in hard water
Detergent
Detergents are salts of sulphonic acids
Detergents are made from hydrocarbons obtained from coal and petroleum.
Detergents are more effective than soaps in hard water.
Excessive use of detergents cause environmental problems
