Aliphatic hydrocarbons are hydrocarbons that do not contain any aromatic rings. They can be either straight-chain, branched-chain (acyclic/open chain), or cyclic alkanes (alicyclic hydrocarbons).
(1) Closed chain hydrocarbons: These are cyclic hydrocarbons.
(2) Acyclic hydrocarbons: These are non-cyclic hydrocarbons.
(3) Open chain hydrocarbons: These are the same as acyclic hydrocarbons.
Since aliphatic hydrocarbons can be acyclic or open-chain hydrocarbons, the correct answer is (4).
Complete the following reactions by writing the structure of the main products: