The type of substance that can conduct electricity in the liquid but not solid phase is an electrolyte.

Here's why:

* Electrolytes are substances that contain ions (charged particles) that can move freely.

* In the solid state, these ions are held in a fixed lattice structure, preventing them from carrying electrical current.

* When melted or dissolved in a solvent, the ions become mobile, allowing them to carry electrical current.

Examples of electrolytes:

* Salts: Sodium chloride (NaCl), potassium chloride (KCl)

* Acids: Hydrochloric acid (HCl), sulfuric acid (H2SO4)

* Bases: Sodium hydroxide (NaOH), potassium hydroxide (KOH)

Note: There are some exceptions. For example, graphite, a solid form of carbon, can conduct electricity due to the delocalized electrons in its structure.