Chromium (Cr) can combine with Chlorine (Cl2) to form Chromium chloride (CrCl3). Which equation is a correction representation of this reaction?
2Cr + 3Cl2 --> CrCl3.
Cr + Cl2 --> CrCl3.
2Cr + Cl2 --> CrCl3.
2Cr + 3Cl2 --> 2CrCl3.