“Bleeding iron” experiment

How to make iron bleed in a solution

Iron is of­ten as­so­ci­at­ed with strength and in­vul­ner­a­bil­i­ty: Iron Man, an iron grip, an iron will. But does iron have a weak spot? In this ex­per­i­ment you’ll see how iron bleeds with­out a sin­gle wound!

Safe­ty pre­cau­tions

Wear pro­tec­tive gloves, a mask and glass­es and work in a well-ven­ti­lat­ed room. Ob­serve safe­ty rules when work­ing with con­cen­trat­ed acids.

Warn­ing! Do not try this at home. Only un­der pro­fes­sion­al su­per­vi­sion.

Reagents and equip­ment:

  • con­cen­trat­ed hy­drochlo­ric acid;
  • 3% hy­dro­gen per­ox­ide so­lu­tion;
  • 10 g of am­mo­ni­um thio­cyanate;
  • iron clip or wire;
  • beaker.

Step-by-step in­struc­tions

In the hy­dro­gen per­ox­ide so­lu­tion dis­solve am­mo­ni­um thio­cyanate and add a few drops of con­cen­trat­ed hy­drochlo­ric acid. Then low­er the iron clip into the re­sult­ing mix­ture.

Pro­cess­es de­scrip­tion

Iron dis­solves in hy­drochlo­ric acid with the for­ma­tion of iron(II) chlo­ride. Then, the iron(II) ion that forms is ox­i­dized by hy­dro­gen per­ox­ide to iron(III), which re­acts with the thio­cyanate ion, form­ing a red com­pound of a tran­si­tion­al com­po­si­tion – iron(III) thio­cyanate.

Fe + 2HCl → Fe­Cl₂ + H₂

Fe²⁺ + H₂O₂ + 2H⁺→ Fe³⁺ + 2H₂O

Fe³⁺ + nCNS⁻ → [Fe(H₂O)ₙ(CNS)₆₋ₙ]ⁿ⁻³

Try it