The dihedral angle between two C-H bonds in the staggered conformation of ethane  is            

1. 60$°$ 

2. 180$°$

3. 0$°$ 

4. 120$°$

In the following, the most stable conformation of n-butane is                

1.

2. 

3. 

4. 

The most stable configuration of n-butane will be                

1. skew boat

2. eclipsed

3. gauche 

4. staggered-anti

The dihedral angle between the hydrogen atoms of two methyl groups in staggered conformation of ethane is:

1. 120° 

2. 180°

3. 90° 

4. 60°

In butane, which of the following forms has the lowest energy?

(1) Gauche form

(2) Eclipsed form

(3) Staggered form

(4) None of these