Answer:
Reagent: aqueous bromine
Observation with ethene: solution turns from brown to colourless.
Observation with ethane: solution remains brown
Explanation:
Unsaturated compound contain C - C double bond while Saturated compound contain C - C single bond. Alkenes with C - C double bonds (unsaturated) can undergo bromination reaction while alkanes (saturated) are not able to do so due to the absence of C - C double bonds.
