Organic compounds which contain a hydroxyl group bounded to a group of hydrogen and carbon only.
General formula Cn H2n + 10H
Ethanol is prepared by fermentation of glucose in the presence of yeast. Yeast contains the enzymes which catalyses the reaction .The reaction is exothermic.
C6 H12 06 (aq) Yeast C2 H5 0H (aq) + C02 (q) + Energy.
Incomplete breakdown of glucose (sugar) to give Ethanol, carbon dioxide and energy
Concentration of Ethanol-by fractional distillation
The distillation which comes off between 780 and 820c is collected. It contains about 5% water.
It is 100% Ethanol
Conc Ethanol is concentrated to absolute ethanol by adding a drying agent like calcium oxide in a stopped flask/corked flask then left to stand for about 24 hours .It is filtered and is re-distilled.
Properties of Ethanol
It is a colourless liquid with L.b.p (volatile) 700 C
It is miscible with water.
Chemical Reaction of Ethanol
It can be dehydrated with conc sulphuric acid or aluminium (iii) oxide inn the presence of heat to give ethane.
Problems associated with excess drinking of alcohol.
- It impairs judgement
- Alcohol is a drug and it is addictive.
- Up to 12% of all road accidents are associated to alcohol.
- Alcoholic have problems in their families and workplaces
- Excessive alcohol intake can damage organ in the body e.g. liver can cause death.
IV- Causes dizziness in vomiting
Manufacture of Ethanol
In the manufacture of Ethanol one of the requirements is a source of starch e.g. barley.
Starch is hydrolyzed to glucose which is then fermented to form ethanol. Ethanol is concentrated by fractional distillation.
Uses of Ethanol
-Solvent in perfumes.
-Used in beers as a part of composition
-Major constituent in alcoholic drinks.
-Used in thermometer
-Used as a source of energy e.g. to drive motor engines.
CARBOXYLIC ACIDS (organic acids) or (alkanioc acids)
They contain the carboxyl group, C00H or – C – O – H
General formula CnH2n + 2 02 or RC00H where n is the number of carbon atoms and R is hydrogen atom or an alkyl group.
Effect on litmus
Blue litmus paper turns red
They react with carbonates and carbonates hydrogen to give salts, carbondoixide and water e.g.
Acid + carbonate organic salt + carbondoixide + water
Slow evolution a colourless gas that turns lime water milky (it’s slow because) the acid is weak)
Reaction with bases or alkalis
Organic acids react with alkalis to give salts water
H+ + OH– [aq] H2O [L]
All organic acids are weak acids and are only slightly ionized in dilute aqueous solution.
THIS VIDEO EXPLAINS MORE ABOUT ALCOHOL IN CHEMISTRY