Compound Z is a dark yellow, crystalline solid. It contains iron(III) ions (Fe3+\text{Fe}^{3+}Fe3+), chloride ions (Cl−\text{Cl}^-Cl−) and water of crystallisation.
A student dissolved some of compound Z in water and then added aqueous sodium hydroxide solution. She obtained a brown precipitate.
Give the formula of the brown precipitate formed in the reaction.
Another student tested a solution of compound Z for chloride ions using dilute nitric acid, followed by a few drops of silver nitrate solution. She obtained a white person precipitate.
Why is the dilute nitric acid necessary in this test?
The empirical formula of compound Z is FeCl3H12O6\text{FeCl}_3\text{H}_{12}\text{O}_6FeCl3H12O6.
Write the formula of compound Z to show its water of crystallisation.
Outline how you would carry out a flame test on a solid sample.
