Which best describes a compound such as sodium chloride?

 Sodium can only be separated from Chloride by chemical means e.g.  electrolysis.

It would be nice if you could state your possible options so it would be easier to confirm but here is what I can best describe about sodium chloride.

Sodium Chloride is a Pure Substance that can be chemically separated.

increased stability in the completion of fluorine's outer shell.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.