by oxygen in the air. Usually dilute sulphuric acid is used, but you can use that here – can you see why?
The usual test for Fe2+ ions in solution is to add sodium hydroxide solution. A green precipitate of iron(II) hydroxide is formed. You will have to make sure you add enough sodium hydroxide solution to neutralise the acid present before the precipitate will appear. (On standing this precipitate slowly turns a rusty brown colour due to oxidation to iron(III) hydroxide by the oxygen in the air). The test for a sulphate is to add barium chloride or barium nitrate solution to another portion of your solution of the tablets. A white precipitate of barium sulphate indicates the presence of a sulphate, provided the solution is still acidic. Always carry out a risk assessment and check with your teacher before starting any practical work.
Related Questions
- Dilute nitric acid is used for this back titration. Why are dilute sulphuric acid and dilute hydrochloric acid not suitable in back titration of insoluble metal carbonate?
- Why is dilute sulfuric acid used rather than deionised water to dissolve the iron tablet?
- Can the SAVe be used in conjunction with supplemental oxygen or medical grade air?
