Class 10th Chapter - Carbon and Its Compounds
Chemical Properties of Carbon Compounds
Carbon
compounds show different chemical properties and some of them are study here-
1. Combustion
Carbon burns in the presence of air (Oxygen i.e. O2)
to produce carbon dioxide (CO2), heat and light. This reaction is
oxidation reaction.
Saturated hydrocarbon gives clean flame while unsaturated
hydrocarbon give yellow flame with too much black smoke.
Example :-
C + O2 --------> CO2 + Heat + Light
CH4 + O2 ------> CO2 + H2O + Heat + Light
CH3CH2OH + O2
--------> CO2 + H2O
+ Heat + Light
2. Oxidation
Removal of e-
is called oxidation. Burning of fuel or carbon compounds is complete
oxidation, but we can also see some incomplete oxidation in chemistry. Oxidizing
agents have the ability to add the oxygen to other substances.
CH3CH2OH + {(Alkaline KmnO4
+ Heat) or (Acidified K2Cr2O7 + Heat)} ---------> CH3COOH
Acidified Potassium Dichromate or Alkaline Potassium Permanganate is example of oxidizing agents.
3. Addition Reaction
Addition reaction are the reactions in which hydrogen
is added at double bond or triple bonds in unsaturated hydrocarbons in the
presence of catalyst like Nickel, Palladium.
R2C=CR2 + H2 + Nickel
Catalyst -------> R2CH-CHR2
Example:- Hydrogenation of vegetable oils with Nickel
as a catalyst.
4. Substitution reaction
Substitution reactions are the
reactions in which hydrogen atoms is replaced by other elements.
CH4 + Cl2 + Sun Light ------> CH3Cl + HCl
Some Important Carbon Compounds
Ethanol and Ethanoic Acid
Ethanol (C2H5OH) and
Ethanoic Acid (CH3COOH) are very valuable carbon compounds.
Ethanol and its Properties:
Ethanol (C2H5OH)
is liquid at room temperature with M.P. 156K and B.P. 351K. Ethanol is present
in all alcoholic drinks and soluble in water. Ethanol is good solvent so used
in many medicines preparations.
Reactions of Ethanol
1. Reaction with Sodium
When sodium is added to ethanol, it produces sodium
ethoxide and hydrogen gas.
2Na + 2C2H5OH ------à 2C2H5O-Na+
(sodium ethoxide) + H2
2. Reaction to produce unsaturated Hydrocarbon
When we heat ethanol at 443K in the presence of excess
concentrated sulphuric acid (H2SO4) produces ethene due
to dehydration of ethanol.
CH3CH2OH + Hot Conc. H2SO4
------à CH2=CH2 + H2O
Conc. Sulphuric acid act as dehydrating agent as it
removes water from ethanol.
Question – What is denatured alcohol?
Answer – ethanol (Alcohol) is used on large
scale in industries as solvent so to avoid any misuse of ethanol we add some
poisonous substances (like methanol) in it and also add some dyes to provide
blue color. This type of alcohol is known as denatured alcohol.
Question – Is alcohol used as Fuel?
Answer
– yes, As alcohol (like Ethanol) on burning in sufficient air gives energy, CO2
and H2O
Ethanoic Acid and Its Properties
Ethanoic
acid is also known as acetic acid, it belongs to carboxylic acid (weak acids)
group. Vinegar is prepared from 5-8% solution of acetic acid in water. Vinegar is
used on large scale for the preparation of pickles (Achar). Chemical formula of
ethanoic acid is CH3COOH.
Reaction of Ethanoic Acid
1. Esterification Reaction
Ester is produced, when ethanoic acid
get react with the absolute alcohol and acid catalyst is used to catalyse this
reaction.
CH3COOH (ethanoic acid) + C2H5OH
(ethanol) + acid catalyst --------> CH3COOC2H5 (ester)
Ester gives sweet smells and esters are used for many
purposes like in making perfumes, flavoring agents etc.
On treating ester with sodium hydroxide solution
(alkali) produces sodium salt of carboxylic acid and alcohol. This reaction is
called as saponification reaction as this reaction is used in the preparation
of soap.
CH3COOC2H5 + NaOH
-----> CH3COONa +
C2H5OH
2. Reaction of Ethanoic Acid with Base
Ethanoic acid reacts with sodium
hydroxide (base) to produce water and salt. Sodium ethanoate also known as sodium acetate.
CH3COOH + NaOH -----> H2O + CH3COONa
3. Reaction of Ethanoic Acid with Carbonates
Ethanoic acid and carbonate reacts to
produce carbon dioxide, water and salt. This salt is commonly known as sodium
acetate.
2CH3COOH + Na2CO3 -------> CO2 + H2O + 2CH3COONa
4. Reaction of Ethanoic Acid with Hydrogen Carbonates
Ethanoic acid and hydrogen carbonate
reacts to produce carbon dioxide, water and salt. This salt is commonly known
as sodium acetate.
CH3COOH + NaHCO3 -------> CO2 + H2O + CH3COONa
Soaps and Detergents
Soap
Soap is used for cleaning purpose. As we
know, most dirt contains oil, so this dirt does not easily remove and also do
not easily dissolve in water.
Soap
molecules are potassium or sodium salt of long chain of carboxylic acids. Ionic
end of soap is hydrophilic so dissolve in water but long carbon chain is
hydrophobic so dissolve in oil. In this way soap molecules form a structure,
this structure is named as ‘micelles’.
To
form micelle hydrophobic end attach
to dirt ( or oil droplet) and hydrophilic end faces outside. This activity
creates emulsion in water. These micelles make dirt (or oil droplets) to
dissolve in water and at last wash out and as a result we get clothes clean.
Detergent
Detergent is also used for cleaning purpose. Soaps are not very
effective in hard water but detergents are very effective in hard water. Detergent
molecules are sulphonate or ammonium salts of long chain of carboxylic acids.
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