Final answer:
The unknown substance is a pure compound that is a liquid at room temperature, has a uniform appearance, and can be broken down chemically by electrolysis.
Step-by-step explanation:
The unknown substance in question is a liquid at room temperature, has a uniform appearance, cannot be physically separated by boiling, and can be broken down chemically by electrolysis. Based on these observations, we can classify this unknown substance as a pure substance because it has a constant composition. More specifically, it is a compound because it can be broken down chemically into simpler components, making it different from an element that cannot be broken down.