hi, I need a reaction between two [or three] chemicals that rapidly changes colour through contact.

If you know any please tell.

thanks.

hi, I need a reaction between two [or three] chemicals that rapidly changes colour through contact.

If you know any please tell.

thanks.

BTB and CO2.

Wait, I shouldn't give you answers, you should be doing your own homework.

Why not universal indicator and acids and bases?

Yeah definitely agree with Squirt, The good old Acids and Bases test with Universal Indicator.

Google :slfg:

Redox ftw.

Potassium Permanganate, KMnO4 + any alkene (like ethene, C2H4 ) = a diol (diethanol, C2H2(OH)2 )

changes from a purple solution to colourless.

There's another one I've learnt in organics as well, can't remember what it is atm.

EDIT:

Dichromate, Cr4O7 + alcohol = a salt or an acid depending on the solution being acidic/basic, can't remember the rest of this equation lol, but it changes from orange to green.

Iodine and a starch.

nice and easy to do as many firstaid kits have iodine in them

awesome thanks