[salah_mez]

Hello,
I did the two reactions ( see the attached picture please ) ,

First reaction : copper electroplating tank ( copper sulphate and water with two copper electrodes ) , when i drop some tin object ,it is plated even it is not connected to the kathode

Second reaction : tin electroplating tank ( tin sulphate and water with two tin electrodes ) , when i drop some copper object ,it is not plated.

please can you tell me what i must add to the tin electroplating solution , so objects droped in the solution will be plated whitout connecting them to kathode.

[vmelkon]

When you put tin in a copper sulfate solution, the tin gives up its electrons to the copper ions, so the tin object gets covered in copper. Tin is more reactive than copper.

If you want to cover something with tin, it would have to be a metal that is more reactive than tin. Look at the eletronegativity of the element. For example, magnesium or zinc.

[salah_mez]

thank you vmelkon for the reply,
i can't change the substrat, it must be copper , are there any way to change the ( Sn/Sn2+) potentiel so it will be big than the Cu/Cu2+ potential, or treat the copper surface to be more electronegative.
regards.