Question

What kind of reaction is `2Al (s)+3Cl_2 (g) -> 2AlCl_3(s)`?

Answer 1

This is formally a redox reaction, though other designations may be possible (but I have not thought of them yet!).

Explanation:

Zerovalent aluminum is OXIDIZED to `Al(III)`; it has formally lost 3 electrons. Zerovalent chlorine gas is REDUCED to `Cl^-`. Diatomic chlorine gas accepted 2 electrons to form 2 equiv of chloride ion, `Cl^-`.