So the answer is: Zn.
(2) Manganese dioxide contained in waste batteries is often used as a catalyst to produce oxygen.
So the answer is: MnO 2.
(3) The nutrient elements necessary for plant growth are nitrogen, phosphorus and potassium, and the substances containing these elements are called chemical fertilizers. Ammonium chloride in waste batteries can be used as nitrogen fertilizer.
So the answer is: NH4Cl. ..