School of Elements – Maharashtra Board Class 10 Solutions for Science and Technology (English Medium)
- The organic compounds having double or triple bond in them are termed as unsaturated hydrocarbons.
- The general formula of alkane is CnH2n+2.
- Hydrocarbons are known as parent organic compounds.
- Covalent compounds are generally CnH2n+2.
- Triple bond can be obtained by sharing three pairs or 6 electrons.
- Hydrocarbons necessarily contain carbon and hydrogen.
- Methanoic acid
Catenation: The property of carbon element due to which its atoms can join each other to form long carbon chains is called catenation.
Types of Carbon Chains:
Functional group: The atom or group of atoms in a molecule which determines the characteristic properties of an organic compound is called the functional group.
All organic compounds are derivatives of hydrocarbons. These are formed by replacing one or more hydrogen atoms in a molecule of hydrocarbon by some functional group. After replacement, a new set of compounds is formed. These compounds have different properties from the parent hydrocarbon.
Example: Methyl alcohol (CH3OH). Here, one hydrogen from methane (CH4) is replaced by an OH group. The OH group is known as the alcoholic functional group.
Homologous series: A group of organic compounds having the same functional group and which can be represented by the same general formula. They show more or less similar properties.
Example: Alkanes: Members of this homologous series have the same general formula CnH2n+2.
In the homologous series alcohols, OH is the same functional group; hence, they show close resemblance in their properties.
Consecutive members of the series differ from one another by the CH2 group, such as methyl alcohol CH3OH and ethyl alcohol C2H5OH.
|1.||A detergent is a sodium salt of an alkyl benzene sulphonate or of a fatty alcohol sulphate.||A soap is a sodium or potassium salt of higher fatty acids.|
|2.||A detergent is more effective
in hard water.
|A soap is less effective in hard water.|
Chain structures of organic compound having six carbon atoms:
Ring structures of organic compound having six carbon atoms:
Alcohols are named alkanols in the IUPAC system.
The reaction in which one or more atom/atoms in a molecule of a hydrocarbon is/are replaced by one or more other atom/atoms is called a substitution reaction.
Example: CH3-CH2-I + KOH → CH3-CH2-OH + KI
Here, the I atom of ethyl iodide is replaced by the OH group from potassium hydroxide.
Unsaturated hydrocarbons, i.e. compounds containing double or triple bonds, readily undergo addition reactions.
As one of the bonds from unsaturated compounds is weak, it can be broken easily, and the reactant adds to the carbon atom of the C=C double and C≡C triple bonds.
An unsaturated compound gets converted into a saturated compound by the addition reaction.
Examples of compounds having covalent bonds: Methane(CH4) and methyl alcohol (CH3OH)
Examples of compounds having ionic bonds:
Sodium chloride (NaCl) and calcium chloride (CaCl2)
Alkanes are hydrocarbons in which carbon atoms are linked to each other only by single bonds.
Further, they are classified as open chain compounds and closed chain compounds.
Open chain compounds also contain a branched chain. Examples: Methane, ethane, propane
In closed chain compounds, two ends of a chain of carbon atoms are joined to form a close chain.
Examples: Cyclopropane, cyclohexane
Hydrocarbons which contain triple bonds between carbon atoms are known as alkynes.
The first member of the alkyne family is acetylene (ethyne) (HC≡CH).