Melting Point
Sodium chloride, also known as salt, is a common and widely used chemical. It is the main component of table salt and is a vital part of our diets and our lives. It is used as a food preservative, as a source of sodium and chloride compounds for use in road deicing, fire extinguisher, water softening and in many industrial applications.
The boiling point of molten sodium chloride is 1,413 degrees celcius.
Whenever we dissolve any ionic compound in water it will always have a high melting and boiling point because the strong electrostatic forces of attraction between the ions requires a lot of energy for breaking the bonds between them. This is the reason why ionic salts like sodium chloride have a very high boiling and melting point as it takes a lot of heat to break those bonds.
So why is it that silver chloride has a lower melting point than sodium chloride?
The answer is simple. In silver chloride the atoms of the metal are held together by metallic bonds which are weaker than those in sodium chloride. These weaker bonds don’t take much heat energy to break and so the silver chloride has a low melting point.
Another reason why the melting point of sodium chloride is higher than that of silver is because the atoms in silver chloride have more coloumbic forces of attraction between them. In silver chloride the positive ions of the ion are surrounded by six chlorine ions while in sodium chloride the ions are surrounded by eight chloride ions. The extra chloride ions create more attraction between them which makes the structure more stable.