Awhite substance melts with some decomposition at 730oc. as a solid it does not conduct electricity, but it dissolves in water to form a conducting solution. with explanation, which type of solid might the substance be?

Ionic solid

Explanation:

Ionic solids -

These are the type of solids , which is composed of ions , which are bond by very strong electrostatic force of attraction , are referred to as ionic solids.

And due to very strong force of attraction between the ions , they generally have very high melting point.

When the solid is dissolved in water , the ions gets separate out , and these free ions are capable to conduct electricity , and hence they are very good conductor in molten form , and are insulator in solid form.

Hence , from the given information of the question ,

The correct term is ionic solids.

the earth would become to overheated and everything alive on it will eventually die from overheating. plants will eventually die as well, water will evaporate, and it will be nothing but a hot planet without anything living on it.