Question 2 - Past Year - 3 Mark Questions - Chapter 4 Class 10 - Carbon and its Compounds

Which compounds are called (i) alkanes, (ii) alkenes and (iii) alkynes? C ₄ H ₁₀ belongs to which of these? Draw two structural isomers of this compound.

Answer

• Alkanes are saturated hydrocarbons i.e. they only contain C-C single bonds. They have a general formula C _n H _2n +2 .
• Alkenes are unsaturated hydrocarbons i.e. they contain C-C double bonds too. They have a general formula C _n H _2n .
• Alkynes are also unsaturated hydrocarbons i.e. they contain C-C triple bonds . They have a general formula of C _n H _2n -2 .

Since C ₄ H ₁₀ corresponds to the general formula C _n H _2n +2 , it is an alkane.

The structural isomers of butane (C ₄ H ₁₀ ) are as follows:

Note: Structural isomers are compounds having the same molecular formula but different molecular structures.