Question

1. What are hydrocarbons? Give examples.
2. Give the structural differences between saturated and unsaturated hydrocarbons with two examples each.
3.  What is a functional group? Give examples of four different functional groups.

Answer 1

1. Those carbon compounds which contain only carbon and hydrogen are called hydrocarbons. For example, methane, ethane, ethene etc.
2. Those hydrocarbons which are linked by single bonds only are called saturated hydrocarbons. For example, methane, ethane, propane etc. 
   

   \[\begin{array}{cc} \ce{H}\\ |\\ \ce{H - C - C}\\ |\\ \ce{H} \end{array}\]	\[\begin{array}{cc} \ce{H}\phantom{...}\ce{H}\\ |\phantom{....}|\\ \ce{H - C - C - H}\\ |\phantom{....}|\\ \ce{H}\phantom{...}\ce{H}\\ \end{array}\]
   Methane	Ethane

   Those hydrocarbons which have double or triple bonds are called unsaturated hydrocarbons. For example, ethene, propene, ethyne etc.
   

   \[\begin{array}{cc} \ce{H}\phantom{...}\ce{H}\\ |\phantom{....}|\\ \ce{H - C = C - H}\\ \end{array}\]	\[\ce{H - C ≡ C - H}\]
   Ethene	Ethyne

     
3. The functional group may be defined as an atom or group of atoms joined in a specific manner which is responsible for the characteristic chemical properties of the organic compounds. The examples are the hydroxyl group (-OH), aldehyde group (-CHO), carboxylic acid group (-COOH), ketones group ( >CO) etc.