Question

In the following skew conformation of ethane, $H^{\prime }-C-C-H^{\prime \prime }$ dihedral angle is

• A. ${58}^o$
• B. ${149}^o$
• C. ${151}^o$
• D. ${120}^o$

Answer 1

The correct option is B ${149}^o$

In Newman projection the angle between two substitutent in same carbon atom is ${120}^o$.
$\text{Given, angle between}{H}^{\prime }-C-C-His{29}^o$
$Anglebetween{H}^{\prime }-C-C-H^{\prime \prime }=(H^{\prime }-C-C-H)+(H-C-H^{\prime \prime })$
$\therefore$ $Dihedralangle,H^{\prime }-C-C-H^{\prime \prime }={29}^o+{120}^o$
$={149}^o$