Question

analyze how the conductivity test worked
how does a conductivity apparatus test whether a
solution has ionic or covalent substances in it?
it fails to light up except in homogeneous
solutions.
it lights up when the leads touch each other.
ions complete the flow of electrons to form a
circuit.
the covalent substances bond to the leads to
prevent the lightbulb from lighting.
done

Explanation:

Conductivity in solutions depends on mobile charge carriers. Ionic substances dissociate into ions in solution, which can carry electric charge to complete the circuit of the conductivity apparatus, making the bulb light up. Covalent substances (non-electrolytes) do not form mobile ions, so they cannot conduct electricity to complete the circuit. The correct option describes the core mechanism of how the apparatus detects ionic substances.

Answer:

Ions complete the flow of electrons to form a circuit.