# Why does Cl- corrode aluminum containers?

I heard that $\ce{Cl^-}$ will corrode aluminum containers. Why? Is it because it would form a galvanic cell or produce coordination compounds?

In general, it should not. Under the right conditions, i.e. acidic conditions at high temperature on a freshly exposed (e.g. scratched) $\ce{Al}$ surface, you could get some oxidation to $\ce{AlCl3}$. One industrial process for producing $\ce{AlCl3}$ is via the reaction:
$$\ce{2 Al + 6 HCl → 2 AlCl3 + 3 H2}$$
at $\mathrm{600-800^oC}$. It would of course happen much more slowly, if at all, at lower temperatures and lower acidity.
In other words, in the absence of this perfect storm of conditions, aluminum cans should be very resistant to corrosion by $\ce{NaCl}$.