Answer:
Acid solutions will be those which lights up a bulb when a circuit is connected through them.
Step-by-step explanation:
Acid solutions such as HCl and HNO3 are polar in nature and permits the flow of electricity through them. Whereas non-polar solutions like ethanol and glucose solution will not allow the flow of electricity through them.
Therefore, when an electric circuit is completed by dipping the nails connected to a battery and a bulb into the different solutions, the lighting up of the bulb indicates which solutions are acids.