Answer:
The new substance which has appeared in the test tube is silver (Ag).
Solid silver that emerges from copper as a precipitate.
Explanation:
This is the reaction
Cu (s) + 2AgNO₃ (aq) → Cu(NO₃)₂ (aq) + 2Ag (s) ↓
It is a redox type
(Cu → Cu²⁺ + 2e⁻) .1 OXIDATION
(Ag⁺ + 1e⁻ → Ag) .2 REDUCTION
Cu + 2Ag⁺ + 2e⁻ → Cu²⁺ + 2e⁻ + 2Ag
