Cyclic hydrocarbons which can be represented as structures containing alternating single and double bonds are called .

Aromatic hydrocarbons

Explanation:

Aromatic hydrocarbons are cyclic hydrocarbons which contain alternate double and single bonds. This means that the double bonds are conjugated. Examples of such compounds include; benzene, naphthalene, anthracene etc. These alternate double and single bonds confer special stability on these species which reflects in their heats of hydrogenation and the difficulty of substitution reaction.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).