When we melt any solid,we get its molten form(that can flow from one place to another).That is liquid.
Similarly, This appies to ice which is a solid at room temperature,but upon the application of heat,it melts and becomes a liquid.Thus molten salt is a liquid because it has become a substance in its molten state that can flow from one place to the other. This law follows the characteristics of liquid as a state of matter.
