Rotation around carbon-carbon single bond of ethane is not completely free. Justify the statement

Explanation

Alkanes can have infinite number of conformations by rotation around C-C single bonds . This rotation around a C-C single bond is hindered by a small energy barrier of 1-20 KJ `mol^(-)` due to weak repulsive interaction between the adjacent bonds. Such a type of repulsive interaction is called torsional strain . In staggered form of ethane, the electron cloud of carbon hydrogen bonds are far apart.
Hence, minimum repulsive force . In eclipsed electron cloud of carbon-hydrogen become close resulting in increase in electron cloud repulsion. This repulsion affects stablity of a conformer.
In all the conformations of ethane the staggered form has least torsional strain and the eclipsed form has the maximun torsional . Hence , rotation around C-C bond in ethtane is not completely free.