You are required to identify the following substances using their properties Substance A. conducts electricity in both solid and liquid state. Substance B. conducts electricity in solid state but its electrical conductivity in liquid state is unknown. Also it burns at a vey high temperature to give off carbon dioxide gas.
C. conducts electricity in liquid state but not in solid state Substance
D. does not conduct electricity in any state
You have to identify that; which substance is an ionic compound, which one is covalent compound , which one is a metal and which one is graphite.

Explanation:

A. conducts electricity in both solid and liquid state.

   Metal

B. conducts electricity in solid state but its electrical conductivity in liquid state is unknown. Also it burns at a vey high temperature to give off carbon dioxide gas.

   Graphite

C. conducts electricity in liquid state but not in solid state

    Ionic compound

D. does not conduct electricity in any state

    Covalent compound

A metal is a substance that conducts both heat and electricity in solid and liquid state. They do this by the presence of free mobile electrons within their atomic space.

Graphite is a non - metal but it has free mobile electrons within its carbon frame work that allows of electrical conduction.

Ionic compounds are conductors only in molten state. In solid state, they do not conduct electricity and are called electrolytes in their liquid or molten form.

Covalent compounds do not ionize in solution and will not have ions which can conduct electric current.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation: