These comprehensive RBSE Class 10 Science Notes Chapter 4 Carbon and Its Compounds will give a brief overview of all the concepts.
RBSE Class 10 Science Chapter 4 Notes Carbon and Its Compounds
→ Carbon is a versatile elements that forms the basis for all living organisms and many of the things we use.
→ The amount of carbon present in the earth’s crust and in the atmosphere is quite meagre.
→ The large variety of compounds is formed by carbon because of its tetravalency and the property of catenation that it exhibits.
→ Covalent bonds are formed by the atoms to achieve completely filled outer most shell.
→ The bond formed by the sharing of one electron pair between two atoms is called covalent bond.
→ Carbon forms covalent bonds with itself and other elements such as hydrogen, oxygen, sulphur, nitrogen and chlorine. The bond between carbon atoms is very strong.
→ Covalently bonded molecules are seen to have strong bonds within the molecules, but inter-molecular forces are weak. This gives rise to the low melting and boiling points of these compounds.
→ Allotropes of Carbon-The carbon occurs in different forms in nature with varying physical properties are called Allotropes. Graphite, Diamond and C-60 (Fullerene) are important allotropes of carbon.
→ Diamond is very hard and bad conductor of heat and electricity while graphite is smooth, slippery and good conductor of heat and electricity.
→ In Fullerenes, the carbon atoms are arranged in the shape of a football.
→ Hydrocarbon-Compounds formed by carbon and hydrogen are called Hydro carbons.
→ In the hydrocarbons double and triple bonds are also present between carbon atoms and carbon chains may be straight, branched or in the form of rings.
→ Compounds having carbon-carbon single bond are called Alkanes. General formula of Alkanes is Cn H2n+2.
→ Compounds which have carbon-carbon double bond are known as Alkenes and the general formula of these is CnH2n
→ Compounds having carbon-carbon triple bond are known as Alkynes. General formula of these is CnH2n-2.
→ Compounds having double and triple bond between carbon atoms are called unsaturated compounds.
→ Compounds of carbon having single bond between the carbon atoms are known as saturated carbon compounds whereas compounds of carbon having double or triple bonds between the carbon atoms are known as unsaturated carbon compounds.
→ Homologous series. A series of compounds in which the same functional group substitutes the hydrogen present in a carbon chain is called Homologous series.
→ The functional groups such as alcohols, aldehydes, ketones and carbonxylic acids gives characteristic properties to the carbon compounds.
→ In the Nomenclature of organic compounds prefix or suffix is used according to the nature of functional group.
→ The suffixes of functional groups are as follows-
(i) Alcohol (-OH) ol
(ii) Aldehyde (-CHO) al
(iii) Ketone (>C = 0) one
(iv) Carboxylic acid oic acid
(v) Alkene (>C = C<) ene
(vi) Alkyne (-C = C-) yne
→ Carbon and its compounds are our major sources of fuels. CO2 and H2O are formed by the combustion of these with the liberation of heat and hight.
→ Saturated hydrocarbons will generally give a clean flame while unsaturated carbon compounds will give a yellow flame with lots of black smoke.
→ Some substances are capable of adding oxygen to others. These substances are known as oxidising agents.
→ Saturated hydrocarbons gives substitution reaction and unsaturated hydrocarbons gives addition reactions mainly.
→ Addition reaction :
Ethanol is liquid at room temperature and ethanol is commonly called alcohol.
→ Ethanol liberates H, gas by the reaction with sodium while ethene (CH2 = CH2) is formed by the reaction with hot and concentrate H2SO4.
→ Pure ethanoic acid (Acetic acid) is called glacial acetic acid because the melting point of this is 290 K hence it often freezes during winter in cold climates.
→ Carboxylic acids reacts with alcohol in the presence of an acid catalyst to give an ester. This reaction is called Esterification.
→ Salt of corresponding acid is formed by the reaction of ester with aqueous base. This reaction is known as saponification because it is used in the preparation of soap.
→ Acetic acid forms salt by the reaction with NaOH, Na2CO3 and NaHCO3.
→ Soaps are sodium or potassium salts of long chain carboxylic acid.
→ Detergents are generally sodium salts of sulphonic acids or ammonium salts with chlorides or bromides ions, etc.
→ Soaps and detergents separates oily dirt by the formation of emulsion of it.
→ Soap does not work in hard water while detergent works in hard water also.
→ The action of soaps and detergents is based on the presence of both hydrophobic and hydrophilic groups in the molecule.