General formula for alcohol: n is positive integer, n = 1,2,3…… The names of alcohols end with ‘-ol’. Examples ethanol. C n H 2n+1 OH
Ethanol is produced through fermentation. By action of yeast, sugars or starch are converted into ethanol.
The fermentation of sugar using yeast is optimum at 37°C. If it get too hot, the enzyme will be destroyed. But if the temperature is too low, the yeast become inactive.
Glucose Yeast contains an enzyme, zymase that helps to break down sugar to produce ethanol and carbon dioxide. (Zymase enzyme) yeast Ethanol + Carbon dioxide C 6 H 12 O 6 2C 2 H 5 OH + 2CO 2
Alcohol is a colourless volatile liquid with a sweet smell. miscible in water. Both the boiling point and melting point increase as the number of carbon atoms in its molecule increase (get larger). The miscibility of alcohol in water decreases as molecules get larger.
Alcohol burns easily with a clear blue flame in a plentiful supply of air to produce carbon dioxide and water only. Alcohol burns easily with a clear blue flame in a plentiful supply of air to produce carbon dioxide and water only. Alcohol + oxygenCarbon dioxide + water
Esterification Reaction of an alcohol with an organic acid catalyzed by little concentrated sulphuric acid to produce an ester. Alcohol + organic acid Concentrated sulphuric acid Ester + Water
Example : Ethanol + ethanoic acid Ethyl ethanoate + water Concentrated sulphuric acid C 2 H 5 OH + CH 3 COOH CH 3 COOC 2 H 5 + H 2 O H 2 SO 4
SOLVENTS Alcohols are good solvents for dissolving organic compound which are insoluble in water. Ethanol : Dissolve shellac, varnishes, perfumes and dyes. Methylated spirit : Solvent for varnishes and paints.
EFFECTS… Health Problem Health Problem Health Problem Health Problem Social Problem Social Problem Social Problem Social Problem Psychiatric Problem Psychiatric Problem Psychiatric Problem Psychiatric Problem
HEALTH PROBLEM Liver diseases such as hepatitis Obesity Heart diseases High blood pressure
EXPERIMENT 4.2 Aim : To study the properties of alcohol. Problem : What are the physical and chemical properties of alcohol. Hypothesis : Alcohol can be identified by their physical and chemical properties.