Test: Alkanes - Homologous Series, Substitution Reaction & Isomerism - JAMB MCQ

Alkanes are saturated hydrocarbons, meaning they contain only single bonds between carbon atoms. The general formula for alkanes is C_nH_2n+2, where "n" represents the number of carbon atoms in the molecule. This formula indicates that alkanes have twice as many hydrogen atoms as carbon atoms, plus two additional hydrogen atoms.

The reaction of alkanes with concentrated sulfuric acid is an example of a substitution reaction. In this reaction, one or more hydrogen atoms in the alkane are replaced by functional groups derived from the sulfuric acid, such as -OH or -SO₃H.

Alkanes are characterized by single bonds between carbon atoms, and they do not have the ability to form carbon-carbon double bonds. Alkenes, on the other hand, are unsaturated hydrocarbons that contain at least one carbon-carbon double bond.

Isomers are compounds that have the same molecular formula, meaning they have the same number and types of atoms, but they differ in the arrangement of atoms. This leads to different structural formulas for isomers.

Hydrogenation isomerism is not a recognized type of isomerism. The correct term for isomerism involving the positioning of hydrogen atoms is positional isomerism.

For the molecular formula C₅H₁₂, three structural isomers are possible: pentane, 2-methylbutane, and 2,2-dimethylpropane. Each of these isomers has a different arrangement of carbon atoms and hydrogen atoms.

Tetrachloromethane, commonly known as carbon tetrachloride, is used as a refrigerant in various applications due to its low boiling point and stability.

Tetrachloromethane is used as a fire extinguisher because it is non-flammable and can effectively displace oxygen, thus preventing combustion.

Dichloromethane, also known as methylene chloride, is commonly used as a solvent in dry cleaning processes due to its ability to dissolve a wide range of organic compounds.

Substitution reactions involve the replacement of one functional group with another in a chemical compound. This can occur in various types of compounds, including alkanes, and often involves the substitution of a hydrogen atom with another atom or group.