Today we opened our second MEL Chemistry box with two experiments using tin (Sn). We made a tin dendrite and grew a tin hedgehog. Both experiments involved preparing a tin chloride SnCl2 solution (by mixing tin chloride with a sodium bisulfate). In the first experiment, we had electric current flow through the solution (by connecting it to batteries via crocodile clips), so it acted like an electrolyte. A tin reduction reaction took place: Sn2+(solution) + 2e–→ Sn(solid)
The tin dendrite grows in the direction that the electric current flows through the solution; from one clip towards the other:
In the second experiment, we simply dropped a piece of zinc into the tin chloride solution. What happened as a result was a substitution reaction: some zinc dissolved into the solution, while tin precipitated on the surface of the zinc pellet in the form of lovely needles:
SnCl2 + Zn → Sn + ZnCl2
Geeks out of the box 