Introduction to Carbon and Its Compounds for class 10th
Carbon is a nonmetallic compound which have 6 atomic number and 12 atomic mass. Carbon formed formed billions of compounds now a days. Carbon have 4 valency, and Carbon formed generally 4 bonds which is covalent in nature.
Note: Covalent Bonds is nothing but it is bond which is made up of shared pair of unpaired electrons. Its electronic configuration is 2,4. Covalent bonds are further classify into 2 bonds that is Sigma Bond and Pi Bond. Sigma bonds will be formed by Axial Overlapping or Head on overlapping(Along the internuclear axis) while Pi Bond will be formed by sideway overlapping(Above and below the internuclear axis).
What is Carbon?
Carbon is a versatile non-metallic element. It is placed at right site of the periodic table which is the 14 Group and 2 Period of the Periodic Table.
Example: ethan, methan, bezene, phenol, aniline etc.
Note: When an element exists in more than one crystalline form, those forms are called allotropes; the two most common allotropes of carbon are diamond and graphite.
What is the Unique Properties of Carbon?
- Tetra Valency: Carbon always show valency 4 in all its compounds.
- Catenation: Carbon has a unique property that it shows catenation property(Self linking property of carbon is called catenation property or tendency. A large number of Carbon atoms are linked together).
- Chain: Carbon atom can form long chains. These chains may be straight or branched.
- Multiple Bonds: Carbon atom can form multiple bonds with each other or with other atoms(Multiple Bonds means Single bond, Double bond and Triple bonds).
- Rings: Carbon atom can form rings with each other and also with some other elements. Examples, Benzene, Pyridine etc.
- Strength of Bonds: Bonds Between Carbon atoms are strong. Bond energy between C-C bond is 83 kcal mol^-1. That means we can say that is this the big reasons why C-atom can form such a large number of compounds.
What is Covalent Bond?
A chemical bond, which is formed by the mutual sharing of electrons between two atoms is called covalent bond. It is denoted by a dash. Example, H-O-H, O=C=O etc.
Covalent bond is further classify in three ways:
- Single, Double and Triple bonds
- Sigma and Pi-bonds
- Polar and Non-Polar
Properties of Covalent Bond
- Covalently bonded molecules have low melting and boiling points.
- Comparatively weaker intermolecular forces, unlike ionic compounds.
- These molecules are generally poor conductor of electricity since no charged particles are formed.
Hydrocarbon
Compounds of carbon and hydrogen are known as hydrocarbons. For example; Methane (CH4), Ethane (C2H6), Ethene (C2H4), Ethyne (C2H2) etc.
Saturated Hydrocarbon (Alkanes): General formula is CnH2n+2. n = number of carbon atoms. In this, the carbon atoms are connected by only a single bond (without any ring). For example; Methane (CH4), Ethane (C2H6) etc.
Unsaturated Hydrocarbons
Alkenes: General formula is CnH2n, where n = number of carbon atoms. In this, the two carbon atoms are connected by double bond.
Alkynes: General formula is CnH2n-2, where n = number of carbon atoms. In this, the two carbon atoms are connected by triple bond.
Isomerism: Compounds having the same molecular formula but different structural formula and properties are known as Isomers and this phenomenon is known as Isomerism.
Structural Isomerism: Compounds having the same molecular formula but different structures are called Structural isomers. Example: Isomers of butane (C4H10), Isomers of pentane( C5H12), Isomers of Hexane (C6H14), etc.
Homologous Series: Series of organic compounds having the same functional group and chemical properties and successive members differ by a CH2 unit or 14 mass units are known as Homologous series. Examples: Next homologous of methane is ethane, next homologous of ethane is propane, etc.
Characteristic of Homologous Series:
The successive members in homologous series differ by CH2 unit or 14 mass unit.
Members of given homologous series have the same functional group.
All the members of homologous series shows similar chemical properties.
Functional Group
An atom or group of atoms present in a molecule which largely determines its chemical properties are called Functional Group.
Examples of IUPAC Nomenclature Following:
Coming Soon…
Chemical Properties of Carbon Compounds:
Some important chemical properties of carbon compounds are as follows:
Combustion: The complete combustion of carbon compounds in the air gives carbon dioxide water and Heat & light.
CH3CH2OH(l) + O2(g) –> CO2(g) + H2O(l) + Heat and light
C(s) + O2(g) –> CO2(g) + Heat and light
CH4(g) + 2O2(g) –> CO2(g) + 2H2O(l) + Heat and light
In presence of limited supply of air, saturated hydrocarbon forms a sooty flame.
Unsaturated hydrocarbons burn with a yellow smoky flame.
The gas and kerosene stove used at home has inlet for air so that, burnt to given clean blue flame.
Due to presence of small amount of nitrogen and sulphur, coal and petroleum produces carbon dioxide with oxides of nitrogen and sulphur which are major pollutant.
Oxidation: Oxidation is the addition of oxygen or there is a loss of electrons or increase the oxidation state of the atom from left side or reactant side to the right side or product side of the reactions. Examples: Oxidation of ethanol in presence of oxidizing agents gives ethanoic acid.
Oxidizing Agents: An oxidizing agent, or oxidant, gains electrons and is reduced in a chemical reaction. Also known as the electron acceptor, the oxidizing agent is normally in one of its higher possible oxidation states because it will gain electrons and be reduced. Example: of oxidizing agents include halogens, potassium nitrate, and nitric acid.
Reduction: It is the removable of oxygen or there is a gain of electrons or decrease the oxidation state of the atom from left side or reactant side to the right side or product side of the reactions. Examples: Reaction of Copper oxide with magnesium to form Magnesium oxide and copper, Reduction of Copper oxide when it reacts with hydrogen gas, etc.
Reducing Agents: A reducing agent, or reductant, loses electrons and is oxidized in a chemical reaction. A reducing agent is typically in one of its lower possible oxidation states, and is known as the electron donor. A reducing agent is oxidized, because it loses electrons in the redox reaction. Examples: of reducing agents include the earth metals, formic acid, and sulfite compounds.
Addition Reaction: Addition of dihydrogen with unsaturated hydrocarbon in the presence of catalysts such as nickel or platinum or palladium are known as Hydrogenation (addition) reaction.
Examples: ethene + hydrogen gas with the presence of catalysts (Ni/Pt/Pd etc.) is gives product ethane.
Note:
Catalyst: Substances that cause a reaction to occur or proceeds to different rate without consuming in it are called a catalyst. For example; Ni, Pt, Pd, etc.
Substitution Reaction: Replacement of one or more hydrogen atom of an organic molecule by another atom or group of the atom is known as Substitution Reaction. Examples: methane gas react with Chlorine gas with the presence of light it produced chloromethane and hydrochloric acid i.e. HCl
Some Important Carbon Compounds :
Ethanol (CH3CH2—OH): Commonly known as Ethyl Alcohol.
Physical Properties:
It is colorless, inflammable liquid.
It is miscible with water in all proportions.
It has no effect on the litmus paper.
Chemical Properties: Coming Soon…
Dehydrating agent: Substances which removes water from ethanol (alcohols) is known as Dehydrating agent. Example: Cone. H2SO4.
Uses: As solvent, as antiseptic (tincture iodine), as anti-freeze in automobiles.
Ethanoic Acid (CH3COOH): Commonly known as Acetic acid. 5-8% of ethanoic acid in water is called Vinegar. The melting point of pure ethanoic acid is 290 K and hence, it often freezes in cold climate so named as glacial acetic acid.
Physical Properties of acetic acid
Ethanoic acid have one type of functonal group which is carboxylic acid.
It is a weak organic acid.
It is a colorless, pungent-smelling liquid.
Miscible with water in all proportions.
Turns blue litmus to red.
Chemical Properties of acetic acid:
- Esterification Reaction: Reaction of ethanoic acid with an alcohol in the presence of a few drops of conc. H2SO4 as catalyst gives a sweet-smelling substance known as Esters, called Esterification reaction. Example: ethanoic acid react with ethenol with the presence of conc. sulphuric acid it produce ester( ethyl ethanoate) and water. Use: Esters are used in making perfumes and flavoring agents.
Saponification Reaction: Reaction of esters with sodium hydroxide, gives alcohol and sodium salt of carboxylic acid (soap). This reaction is known as Saponification Reaction. Example: ethyl ethanoate react with sodium hydroxide with the presence of sulphuric acid it produced ethanol and sodium ethanoate. - Reaction with Carbonates and Hydrogen Carbonates: Ethanoic acid reacts with sodium carbonates and sodium hydrogen carbonates to give rise to a salt, carbon dioxide and water. Examples: Coming Soon… Uses: Used as vinegar.
Used as raw material for the preparation of acetyl chloride and esters.
Soap: Sodium or potassium salts of long chain fatty acids is called Soap.
General formula: RCOO–Na+
Detergent: Ammonium and sulphonate salts of long chain fatty acids are called Detergent.
Example: CH3—(CH2)11—C6H4—SO3Na.
Hard and Soft Water: Water that does not produce lather with soap readily is called Hard water and which produces lather with soap is called Soft Water. Hardness of water is due to the presence of bicarbonates, chlorides and sulphate salt of calcium and magnesium.
Difference between soaps and detergents:
| Soaps | Detergents |
| (i) These are sodium or potassium salts of long chain fatty acids. | (i) These are ammonium and sulphonate salts of long chain fatty acids. |
| (ii) Ionic part of the soap is —COO–Na+ | (ii) Ionic part of detergent is —OSO3-Na+. |
| (iii) Their efficiency decreases in hard water | (iii) Their efficiency is unaffected in hard water. |
| (iv) Soaps are biodegradable. | (iv) Detergents are non-biodegradable. |
Advantage of Detergents: The main advantage of detergent over soaps is that soaps cannot be used in hard water for washing because hard water reacts with soap to form curdy white precipitate called Scum. Example: Sodium stearate react with calcium chloride it produce calcium stearate and sodium chloride. Thus, in hard water, soap does not give lather while detergent does.
Cleansing Action of Soaps and Detergents: Both soaps and detergents cantains two parts. A long hydrocarbon part which is hydrophobic (water repelling) in nature and a short ionic part which is hydrophilic (water attracting) in nature.
The hydrocarbon part of the soap molecule links itself to the oily (dirt) drop and ionic end orients itself towards water and forms a spherical structure called micelles. The soap micelles helps in dissolving the dirt in water and wash our clothes. Micelles formation image coming soon…