Question

Distinguish alkanes from alkenes and each of them from alkynes, giving
one example of each. Draw the structure of each compound cited as example to justify your answer.
hydrocarbons

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Answer 1

Distinguish alkanes from alkenes and each of them from alkynes giving one example of each. Hydrocarbons are compounds that are made only of carbon and hydrogen atoms. Alkenes: Alkenes are unsaturated aliphatic hydrocarbons that contain one double bond.

Answer 2

Hydrocarbons:-

The compounds composed only of carbon and hydrogen are known as hydrocarbons.

Alkanes:-

✦Hydrocarbons in which all the linkages between the carbon atoms are single covalent bonds are known as alkanes.

✦General formula: $\sf C_n H_{2n+2}$

✦They are saturated hydrocarbons.

✦They undergo substitution reaction.

✦They are less reactive because of the non-availability of electrons in the single covalent bond.

Ex:- $\sf CH_4$(Methane)

Alkenes:-

✦Hydrocarbons in which two carbons are connected by double bond are known as Alkenes.

✦General formula: $\sf C_n H_{2n}$

✦They are unsaturated aliphatic hydrocarbons.

✦They undergo addition reaction.

✦They are most reactive than alkanes and alkynes because of the presence of  double bond.

Ex:- (Ethene)$\sf C_2 H_4$    

Alkynes:-

✦Hydrocarbons in which the two carbon atoms are connected by triple bond are known as Alkynes.

✦General formula: $\sf C_n H_{2n-2}$

✦They are unsaturated aliphatic hydrocarbons.

✦They undergo addition reaction.

✦They are more reactive than alkanes due to the presence of a triple bond.

Ex:- (Ethyne) $\sf C_2 H_2$

Note:- Refer to the attachment for structures.

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