# What happens to a solid whose vapour pressure reaches 760 mm Hg at temperatures which are lower than the triple point?

(a) it melts

(b) it sublimes

(c) it burns

(d) it evaporates

Toolbox:
• Solid-Gas Equlibrium
• Only those solids sublime whose vapour pressure reaches 760 mm Hg at temperatures which are lower than their triple point and consequently these substances evaporate at 1 atmospheric pressure without even melting