Answer to Question #161303 in General Chemistry for mike

Question

Displacement reactions can also occur between metals and metal oxides. The principle is the same as for the reactions between metals and metal salt solutions. A more reactive metal will displace a less reactive metal from its oxide. Usually the mixture has to be heated.

Chromium is sometimes made by the following reaction:

2Al(s)   +   Cr2O3(s)     →     Al2O3(s)   +   2Cr(s)

Which metal is the more reactive of the two? Give a reason for your answer.

Answer 1

Aluminum is more reactive than chromium.

The reason is that Aluminum which is more electropositive than Chromium displaces chromium from it's oxide Cr2O3