Chemical properties of carbon

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 + O_{2 ——->} CO₂ + H₂O + heat and light

• Saturated hydrocarbon gives clean flame while unsaturated carbon compounds give yellow flame with lots of black smoke.

NOTE–

• 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.

OXIDATION -:

• 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

ADDITION REACTION-:

• 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.

SUBSTITUTION REACTION-:

• A reaction in which one functional group or atom is replaced by another functional group or atom is called substitution reaction.

Example-

 

Important compounds of carbon

1. 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.
2. 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