Final answer:
The low melting point of zinc nitrate is true because it is attributed to the loss of the hydrate's water and subsequent decomposition as opposed to actual liquefaction. This is due to the physical change that occurs as the hydrate loses water when heated, followed by decomposition of the anhydrous salt.
Step-by-step explanation:
The statement is true. The low melting point of zinc nitrate is indeed attributed to the loss of water from the hydrate salt and then subsequent decomposition, rather than actual liquefaction. When a typical ionic compound like zinc nitrate, which often exists as a hydrate with water molecules incorporated into its crystal structure, is subjected to heat, it loses its water of hydration. This process is a physical change where the solid turns into a gaseous form when heated. After losing water, the dehydrated salt may undergo decomposition before it reaches its literal melting point that would occur in a pure anhydrous state.
To understand this concept, consider the general behavior of solids upon heating—as a solid is heated, its particles vibrate more rapidly, absorbing kinetic energy and breaking down the solid structure as they begin to melt. Hydrate salts like zinc nitrate are distinct in that they may first lose water at temperatures significantly lower than their melting points, thereby altering the material before it actually melts. In contrast, ionic compounds with high lattice energies, such as sodium chloride, require much higher temperatures to break apart the ionic lattice for the compound to melt.