If the triple point pressure of a substance is greater than 1 atm, which two of the following conclusions are valid?
1) The liquid state of the substance cannot exist.
2) The gaseous state at 1 atm pressure cannot be condensed to the solid at the triple point temperature.
3) The melting point of the solid must be greater than 0 C.
4) The liquid state cannot be maintained in a beaker open to air at 1 atm pressure.
5) The melting point and boiling point of the substance are identical.
6) The solid and liquid states of the substance cannot coexist at equilibrium.