Question

What happens to sound when it strikes a surface

Answer 1

When sound strikes a surface, some of the sound get absorbed by the surface and some of it gets reflected. If the surface is hard most of it gets reflected and a little is absorbed and vice versa. 

Answer 2

If the surface can vibrate, then the surface vibrates, absorbing most of the energy.  That is how our ear  senses the sound waves falling  on the ear drum.

Part of if is transmitted as the vibrations of the particles in the medium.  If the surface is hard and smooth, then it is reflected.  If the surface is soft and rough, then the reflected sound does get cancelled due to interference.  The energy is absorbed does not go far in the medium if it is soft.