NaCl when in solid state does not conduct electricity
while it does in aqueous solution.
Explanation:
NaCl (or what we call common salt) first needs to be either
melted or dissolved in a solution for it to conduct electricity. The reason for
this is that electrons in a solid state does not have enough freedom to move to
either the Cathode (-ve) or to the Anode (+ve). So in a liquid state the
electrons are now free enough to move.
The answer is state.
That is the state would be least helpful in determining whether a substance is a metal or a nonmetal. The state can only tells that a compound is liquid, gas or solid. But it can't tell whether a substance is metal or non-metal. So it is the least helpful in determining whether a compound is metal or non-metal.
