How many gauche conformations are possible for n- butane ?

How many isomers are possible for butane?

How many extreme conformations can be drawn for n -butane if we consider rotation about the C_(2) and C_(3) bonds?

How many structural isomers are possible for butane?

The number of conformational isomers possible of n-butane about C_(2)-C_(3) bond

The most stable conformation of n- butane is

How many optically active stereomers are possible for butane - 2,3- diol ?