Answer:
Lead (II) iodide
Explanation:
The reaction of lead (II) nitrate, Pb(NO₃)₂ with KI is:
Pb(NO₃)₂(aq) + 2KI(aq) → KNO₃(aq) + PbI₂(s)
This is a typical double-replacement reaction where anions and cations exchange its couple.
All nitrates are solubles, thus, KNO₃ is not the precipitate.
The only possibility of precipitate is PbI₂,
Lead (II) iodide, a yellow and insoluble solid...
This is a reduction reaction as the oxide(oxygen) is taken away from the metal =]
I can’t use evidence from the picture but the green slime from the pond that they are talking about is called Algae, which is alive and can grow quickly with sunlight or any other source of energy such as water and carbon dioxide. Hope this helps!!