Question

The gas which exist in solid liquid and gaseous form

Answer 1

if u ask for a substance then it would be water which exists in all three states but about gas I am not too sure

Answer 2

i think its helium bcoz

Rob Hooft said that  some elements like helium have multiple triple points. Helium can’t form a solid at zero pressure (I think it’s the only element), but it has two superfluid phases. According to the phase diagrams I’ve found, Helium has FOUR triple points: superfluid B - liquid - gas, solid - liquid - superfluid A, solid - superfluid A - superfluid B, and superfluid A - Superfluid B - liquid.