Several threads, current and past, have discussed pennies with no copper, just zinc, showing. It's time to clear up a few misconceptions here. Acid will not dissolve Copper, at least not as easily as many of you would seem to believe. Hydrocholric acid does not react with Copper at all. Sulphuric acid and Nitric acid will react with Copper, but only with applied heat and added oxygen. The reactions of these two acids produce poisionous gasses so it's not something you'd want to do at home without safety precautions and good ventilation. Sulphuric and Nitric acids will react with (dissolve) Zinc so if either are used to remove the Copper from a plated penny, the Zinc will also be dissolved and you won't wind up with a Copperless Zinc penny, just a blob of metal. If you want to remove the Copper from a plated penny, use Ferric Chloride. This will remove the Copper and leave the Zinc untouched. It is safe to handle and doesn't produce dangerous afterproducts. If you want to remove the Zinc from a plated penny and leave the Copper shell, file a small spot on the rim to expose the Zinc. Then place the penny in Hydrochloric acid. The acid won't touch the Copper but it will dissolve the Zinc from inside, leaving a hollow shell of Copper. Hydrochloric acid is very corrosive and will cause any iron or steel anywhere near it to rust. I'm not advocating doing any of the above experiments, I'm just a bit weary hearing "dipped in acid" as an explanation by those who don't really know what they're talking about. Even "safe" chemicals need to be handled correctly and acids have obvious dangers. If anyone decides that, since they didn't blow up their house with their home chemistry set that they can handle a simple experiment with a penny, don't blame me when you're sitting in the ER with holes burned through your skin.
Handbook of Chemistry and Physics disagrees with you about copper and HCl at room temperature. Now, it does not show that it bubbles and immediately goes away, but it does react significantly. It also shows copper will even "dissolve" in citric and acetic acids. BTW, that is exactly what you do when you use vinegar (acetic acid) to bring out the dates on buffaloes. There are numerous threads here showing the results.
In general, an acid will not react with copper, unless there is oxygen present. This is why Sulphuric Acid (H2SO4) and Nitric Acid (HNO3) will react and Hydrochloric Acid (HCl) will not. Copper is lower on the reactive scale than Hydrogen and will not displace it from the HCL. Hydrochloric Acid can be made to work on Copper only if Oxygen is added. The simplest way is to add Hydrogen Peroxide (H2O2) to the mix. The Oxygen adds an intermediate reaction which will end with the Copper being "dissolved." If you drop a brown penny into Hydrochloric Acid you will get a reaction only because the acid is reacting to the Cupric Oxide on the surface of the penny.
I appreciate your point David. However, to me, any type of coin that can be recreated this way has to be assumed to have been absent extraordinary proof. I like it to miscut bills. If a bill was ever sold in uncut sheets then I believe all miscuts on those have to be assumed as done outside government control. Same with coins. Absent extraordinary proof otherwise, one simply has to assume the most likely cause.
I am sorry, but that simply is not so. It will not react as rapidly as zinc, but it does react with unoxidized copper.
Rim: I don't suggesst that Ask.com is neccessarily the go-to source for everything but you might take a look at this: http://www.ask.com/questions-about/Will-HCL-CU-React#anchl_3 Here is an actual experiment: http://www2.uni-siegen.de/~pci/versuche/english/v44-24-1.html And a video of Cu in HCl: http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA3/MVHTM/VOLTAGE/VOLTAGE2.HTM The Reactivity Series shows which elements react with water, acid and oxidizing acids: http://en.wikipedia.org/wiki/Activity_series Quite simply: Cu + HCl --> no reaction medoraman: In effect, what you're saying is that you don't really know, but someone said that some penny was dipped in acid to remove the copper so it must be so. I'm not necessarily saying that some acids won't react with Copper, but that Hydrochloric Acid will not. The acids that will react with Copper either need equipment and precautions not normally found at home, or they require time and heat to produce any reaction in a reasonable amount of time. If you have a ventilated exhaust hood, Pyrex glassware and a laboratory heater then have a go at it. Alternatively, you can use a weak acid like citric or acetic, put your penny in and wait a month or two to see if anything happens.
Of course. I never say I know what is done to a coin once it leaves the mint. I was simply saying if a coin can easily be explained by an after mint action, then one should assume that unless it can be PROVEN it was made at the mint. That is all.
Believe me, DavLdh, I trust the Chemical Engineering Handbook a lot more that Kimberly L - even my ancient version of it. BTW, you did notice that I stated that it does not react violently, did you not?
When I get a chance I'll do the three experiments: 1. Cent in HCl. 2. Cent with scratch (exposing the zinc) in HCl. 2. Cent in Ferric Chloride solution.
That will be great. I hope you are aware of how to handle these chemicals. HCl fumes will react with anything in the area so ventilation is recommended. FeCl3 is a corrossive and will also stain just about anything it comes in contact with. Rubber gloves, eye protection, ventilation, etc are de rigueur. You may need more than a small scratch on the cent. A filed area on the edge about 2mm square should work; you need enough area for the acid to actually get into the cent. We await your results.
