Gold, like iron and copper, can have more than one monatomic cation. Knowing this, a mining company wanted to find the formula of a gold - chlorine compound that it has come across during its mining operation. A 115 milligram sample of this compound was dissolved into water and treated with an excess of silver nitrate to convert all of the chloride ion into a precipitate of silver chloride. If 163 milligrams of silver chloride was filtered out, determine the formula of the gold compound.
1. AuCl
2. AuCl2
3. AuCl3
4. AuCl4
5. AuCl5