If i had a compressed with a million ft/lbs and dropped it into acid where it instantly disintigrated?

When you compress the spring, you distort the lattices of the crystals that make it up. The potential energy is stored in the chemical bonds between atoms in the lattices.

If these bonds were broken, the atoms would still have the same energies, but would no longer be tied into a crystal. Their potential energy would become the kinetic energy of motion. The kinetic energy of atoms and molecules is measured by their temperature.

Formerly metallic solid spring would become a hot gas. In other words, the potential energy would be converted to kinetic energy (high temperature) and you would see an explosion.

the compressed coil spring when you drop into an acid does not disintegrate until the material that holds the spring's tensile strenght is damaged by the reation of acic

Well the PE would be transfer to the acid and create a pop effect when disinigrating.