A student analyses a solution of an unknown salt.
The results are shown in the table below:
| Test | Observation |
|---|---|
| Reaction with aqueous sodium hydroxide, NaOH(aq)\text{NaOH(aq)}NaOH(aq) | Brown precipitate |
| Reaction with acidified aqueous silver nitrate, AgNO3(aq)\text{AgNO}_3\text{(aq)}AgNO3(aq) | White precipitate |
What is the formula of the salt?
FeCl2\text{FeCl}_2FeCl2
FeCl3\text{FeCl}_3FeCl3
CuCl2\text{CuCl}_2CuCl2
Fe(NO3)3\text{Fe(NO}_3)_3Fe(NO3)3
