Chemical properties of carbon
A 🙂 COMBUSTION
B 🙂 OXIDATION
C 🙂 ADDITION REACTION
D 🙂 SUBSTITUTION REACTION
COMBUSTION -: Carbon, in all its allotropic forms, burns in oxygen to give carbon dioxide along with the release of heat and light.
(A) C + O2 —–> CO2 + heat and light
(B) 2CH4 + 4O2 ——> 2CO2 + 4H2O + heat and light
(C) CH3CH2OH + O2 ——-> CO2 + H2O + heat and light
- Saturated hydrocarbon gives clean flame while unsaturated carbon compounds give yellow flame with lots of black smoke.
- Fuels such as coal and petroleum have some amount of nitrogen and sulphur in them.
- Their combustion results in the formation of oxides of sulphur and nitrogen which are major pollutants in the environment.
- Flame is only produced when gaseous substances burn.
- When wood or charcoal is ignited, the volatile substances present vaporize and burn with a flame in the beginning.
- A luminous flame is seen when the atoms of the gaseous substance are heated and start to glow.
- The colour produced by each element is a characteristic property of that element.
- loss of electron or addition of oxygen is known as oxidation.
- Substances which are capable of adding oxygen to others.
- These substances are known as oxidizing agents.
- Examples- Alkaline potassium permanganate or acidified potassium dichromate
- Unsaturated hydrocarbons add hydrogen in the presence of catalysts such as palladium or nickel to give saturated hydrocarbons.
- EXAMPLE- Hydrogenation of vegetable oils using a nickel catalyst.
- Hydrogenation of ethene to ethane using a nickel catalyst.
- A reaction in which one functional group or atom is replaced by another functional group or atom is called substitution reaction.
Important compounds of carbon
- Ethanol– Ethanol is commonly called alcohol and is the active ingredient of all alcoholic drinks. It is used as good solvent tincture iodine, cough syrups, and many tonics.
- ethanol reacts with sodium leading to the evolution of hydrogen. This reaction is used to detect presence of ethanol by evolution of hydrogen gas.
-Ethanol reacts with concentrated sulphuric acid to form unsaturated compound.
2. ETHANOIC ACID– commonly called acetic acid
- 5-8% solution of acetic acid in water is called vinegar and is used widely as a preservative in pickles.
- Pure ethanoic acid freezes during winter, it is also known as glacial acetic acid.
Esterification reaction: formed by reaction of an acid and an alcohol.
–Saponification reaction: reaction of ester with strong base is used to form soap. Hence it is known as Saponification reaction.
- Ethanoic acid reacts with a base such as sodium hydroxide to give a salt (sodium ethanoate or commonly called sodium acetate) and water:
NaOH + CH3COOH ——-> CH3COONa + H2O