<span>
Phenobarbital is derivative of
Barbituric Acid and Barbituric Acid is derivative of
Urea. (structures shown in Fig below)
Urea has H</span>₂N- group attached to Carbonyl Group (C=O), and such class of comounds conataining H₂N-C=O bond are called as Amides.
Result: So, <span>Phenobarbital belongs to
Amides.</span>
Kevlar would be the answer!! enjoy the rest of your day broskies!!!
Explanation
Radius of neon atom : 69 pm = 
Volume occupied by the one atom:

given that
atoms are present in 1L
1 L = 0.001 
The volume occupied by the
neon atoms

Fraction of volume occupied by the neon atom:


The fraction of of volume occupied by the neon atom is very less than the 1 L which indicates the presence of large amount of empty space between the atoms of the gas.