What is the effect of adding ferrous sulfate solution to immigrants who have been left for too long and have not been fully shaken and washed?

Ferrous sulfate can be used to make water purifying agent. It is often made of scrap iron (containing a small amount of alumina and iron oxide, etc.). ) In industry.

(1) Degreasing: Use hot water and detergent to remove the oil stain on the surface of iron filings, indicating that detergent has _ _ _ _ function.

(2) Alumina removal: hot sodium hydroxide solution is added to the iron filings, and the chemical equation of the reaction is: Al2O3+2NaOH+3R2AAL (OH) 4, then the chemical formula of R is _ _.

(3) Preparation of ferrous sulfate crystals, the process of which is shown in the figure:

(1) In step I, pure iron powder is added to make iron react with ferric sulfate to generate ferrous sulfate, and the chemical equation of the reaction is _ _.

(2) ② The curve of solubility of FeSO4 _ 4 with temperature is shown in the figure. The reason why the solution in step I is best filtered at 63℃ is _ _.

③ The FeSO4 _ 4 _ 4 crystal obtained by filtration in the second step was washed with _ _ (fill in the serial number).

A water b ferrous sulfate solution c saturated ferrous sulfate solution

Test answer

Online course

Please click to enter a picture description.

Ferrous sulfate solution is light green, because ferrous ions are light green in ferrous sulfate solution and water.

Ferrous sulfate solution is an unstable solution, which is basically prepared at present. If the ferrous sulfate solution is left for a long time, the ferrous ions in it will react with the oxygen ions in the water, and the ferrous ions will be oxidized into trivalent iron, so the green ferrous ions will become yellow trivalent iron ions. So many people mistakenly think that ferrous sulfate solution is yellow, which is wrong.

In the laboratory, it can be obtained by the reaction of copper sulfate solution with iron. The weather will get better in dry air. It is easy to oxidize into brown basic ferric sulfate insoluble in water in humid air. 10% aqueous solution is acidic to litmus (Ph value is about 3.7). When heated to 70 ~ 73℃, 3 water molecules are lost, 6 water molecules are lost at 80 ~ 123℃, and they are converted into basic ferric sulfate above 156℃.