Answer
The figure requires a chemical membrane in order to complete the circuit to power the lightbulb via conducting ions. If there were no chemical membrane, the conducting ions would not be able to pass through. If there were no separator at all, the circuit would short out.
Work Step by Step
The figure requires a chemical membrane in order to complete the circuit to power the lightbulb via conducting ions. If there were no chemical membrane, the conducting ions would not be able to pass through. If there were no separator at all, the circuit would short out.