Zn + HCl and steel or iron plating

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The discussion centers around the reaction of zinc dissolved in hydrochloric acid (HCl) and the unexpected outcome of a purple/violet liquid, presumed to be zinc chloride. The user observed a copper/brass-colored plating on mild steel or iron when applying the solution, despite having no copper in the mix. The color change raises questions about the composition of the solution, as pure zinc solutions are typically colorless. The user notes that the zinc source was an etching plate claimed to be 99.95% pure, but also mentions the potential contamination from a zinc carbon battery case used in the process. This contamination could explain the unexpected coloration and suggests that the solution may not be purely zinc chloride. The user is seeking clarification on the nature of the coloration and its implications for their electroplating plans.
Roger Paine
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I dissolved zinc in HCl until it stopped fizzing - all the Zn is gone so there may be some HCl left. I have a purple/violet liquid that I assume is zinc chloride. When I brush newly cut mild steel or iron with the solution, I get copper/brass coloured plating that does not rub off. I have no copper in the mix. My plan was to use the ZnCl to electroplate steel that has been prepared by electroplating copper which I was then intending to heat to get brass plate. The colour that I'm getting just by brushing the steel and iron with my solution is almost close enough to brass to make the rest of the process redundant. What's going on - what is the copper/brass colour? Anyone? cheers Roger
 
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If the solution is purple/violet it was not a pure Zn, as its solutions are colorless.
 
Borek said:
If the solution is purple/violet it was not a pure Zn, as its solutions are colorless.
My zinc came from an etching plate which is marketed as being 99.95% pure zinc. The acid is 35% that I brought from the hardware shop... come to think of it, I did initially put a zinc carbon battery case in there to start with... washed all the electrolyte off and wire brushed it... maybe that isn't a good source for zinc.
 
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