Least energetic conformation of cyclohexane is

Cyclohexane exists in two forms and these are chair and boat conformations. In the chair form, all the \(\mathrm{C}-\mathrm{H}\) bonds on adjacent carbon atoms, are in the skew position. In the boat form, four of the \(\mathrm{C}-\mathrm{H}\) bonds are skew \((1,2 ; 3,4 ; 4,5\) and 6,1\()\) and two are eclipsed \((2,3\) and 5,6\()\). At the same time, there will also be some bond opposition strain for these two pairs of eclipsed bonds and also steric repulsion between the hydrogen pointing towards each other at 1 and 4 .



Hence, the total strain in the boat conformation is larger than that in the chair conformation and consequently the former is less stable than the latter.