Weird Science

Lots of Foam – The Catalytic Decomposition of Hydrogen Peroxide

Polish ver­sion is here

Spec­ta­cu­lar Reac­tion

Per­hy­drol is a 30% solu­tion of hydro­gen pero­xide in water. It is a color­less and odor­less liquid with a den­sity sli­gh­tly higher than water. It exhi­bits strong cor­ro­sive pro­per­ties, cau­sing loca­li­zed necro­tic damage upon skin con­tact.

Hydro­gen pero­xide is widely used as a power­ful oxi­di­zing agent in the che­mi­cal indu­stry. It is com­monly employed in the pro­duc­tion of various orga­nic dyes, as well as in the syn­the­sis of explo­sive pero­xi­des such as ace­tone pero­xide.

What's more, hydro­gen pero­xide is also highly unsta­ble and rea­dily decom­po­ses in the pre­sence of cer­tain cata­ly­sts into oxy­gen and water, fol­lo­wing the reac­tion:

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This reac­tion will be used to cre­ate che­mi­cal foam.

Let's Get to Work!

The list of requ­i­red mate­rials is short:

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War­ning: Per­hy­drol is a strong oxi­di­zer and highly cor­ro­sive. Pro­tec­tive glo­ves and safety gog­gles must be worn at all times! The resul­ting foam con­ta­ins iodine, which can per­ma­nen­tly stain the skin. Avoid direct con­tact with bare hands. The author assu­mes no respon­si­bi­lity for any damage or harm that may result. Con­duct this expe­ri­ment at your own risk!

Care­fully pour the hydro­gen pero­xide into a nar­row-nec­ked con­ta­i­ner. Next, add a few drops of dish­wa­shing liquid. Place the con­ta­i­ner on a smo­oth sur­face and quic­kly add a small amo­unt of potas­sium iodide. A vigo­rous reac­tion will begin, pro­du­cing a large amo­unt of hot foam:

Even a small amo­unt of the mixture can gene­rate a sub­stan­tial volume of foam:

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The expla­na­tion for this phe­no­me­non is sim­ple. Potas­sium iodide acts as a strong cata­lyst for the decom­po­si­tion of hydro­gen pero­xide. With this cata­lyst, hydro­gen pero­xide bre­aks down accor­ding to the equ­a­tion above, for­ming water and oxy­gen. In the pre­sence of deter­gent in the solu­tion, the rele­a­sed oxy­gen beco­mes trap­ped, resul­ting in the for­ma­tion of foam.

Ano­ther expe­ri­ment uti­li­zing hydro­gen pero­xide is the rapid decom­po­si­tion of per­hy­drol.

Have fun expe­ri­men­ting!

Fur­ther rea­dings:

Marek Ples

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