JEE Main & Advanced Chemistry Organic Chemistry: Some Basic Principles & Techniques / कार्बनिक रसायन : कुछ मूलभूत सिद्धांत एवं तकन Alkyl groups

These are univalent groups or radicals obtained by the removal of one hydrogen atom from a molecule of a paraffin. The symbol 'R' is often used to represent an alkyl group.

           \[\begin{align}   & \text{(Alkane) }{{C}_{n}}{{H}_{2n+2}}\xrightarrow{-H}{{C}_{n}}{{H}_{2n+1}}\text{ (Alkyl group)} \\  & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(R-H)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(R-) \\ \end{align}\]           

Alkyl groups are named by dropping-ane from the name of corresponding paraffin and adding the ending'yl.

Alkyl groups derived from saturated hydrocarbons having three or more carbon atoms exist in isomeric forms.

Similarly, removal of different H atoms in pentane gives the following radicals :           

\[\underset{n-Pentyl}{\mathop{C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}-}}\,\];\[\underset{\text{Isopentyl}}{\mathop{\underset{C{{H}_{3}}\,\,\,\,\,\,\,\,\,\,\,\,}{\mathop{\underset{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}{\mathop{C{{H}_{3}}CHC{{H}_{2}}C{{H}_{2}}-}}\,}}\,}}\,\]; \[\underset{\text{Neopentyl}}{\mathop{\underset{\,\,\,\,\,\,C{{H}_{3}}}{\mathop{\underset{|\,\,\,}{\mathop{\overset{\,\,\,\,C{{H}_{3}}}{\mathop{\overset{|\,\,\,\,}{\mathop{C{{H}_{3}}CC{{H}_{2}}-}}\,}}\,}}\,}}\,}}\,\];\[\underset{\sec -\text{Pentyl}}{\mathop{\underset{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}{\mathop{C{{H}_{3}}CHC{{H}_{2}}C{{H}_{2}}C{{H}_{3}}}}\,}}\,\]; \[\underset{tert-\text{Pentyl}}{\mathop{\overset{\text{C}{{\text{H}}_{\text{3}}}\,\,\,\,}{\mathop{\underset{|\,\,\,\,\,\,\,\,}{\mathop{\overset{|\,\,\,\,\,\,\,\,\,}{\mathop{C{{H}_{3}}CC{{H}_{2}}C{{H}_{3}}}}\,}}\,}}\,}}\,\] Unsaturated groups or radicals