Question

Use of Metal	Property
Zinc in Galvanization Aluminium in Thermite welding

Answer 1

Use of Metal

Property

Zinc in Galvanization Aluminium in Thermite welding

Zinc $\left(\mathrm{Zn}\right)$ is more reactive than iron$\left(\mathrm{Fe}\right)$ and is resistant to corrosion. Therefore, it is coated over iron $\left(\mathrm{Fe}\right)$by galvanization, to prevent the corrosion of iron$\left(\mathrm{Fe}\right)$. Aluminium$\left(\mathrm{Al}\right)$ is a good reducing agent and it has a high affinity with oxygen$\left({\mathrm{O}}_2\right)$. The reaction is highly exothermic. In the Thermite process, aluminium $\left(\mathrm{Al}\right)$powder is heated with ferric oxide$\left({\mathrm{Fe}}_2{\mathrm{O}}_3\right)$. Here, the ferric oxide$\left({\mathrm{Fe}}_2{\mathrm{O}}_3\right)$ is reduced to iron$\left(\mathrm{Fe}\right)$ which is in the molten state. It drops into a broken railway track and joins it.