Do you guys remember that experiment you did on school where you power a calculator with some wires, two different metals and a lime (or lemon)? Well, I was wondering: Would the lime taste different after the battery you created runs out of power? Will anything happen to the lime, in fact, or only the metal pieces that are stuck to the fruit change?
I would suspect that they would taste very metallic, after having metal ions sucked off of the plates and into the lime.
I wouldn’t recommend tasting them.
Your typical lime battery is going to be a zinc electrode (often a dime or a roofing nail is used), a copper electrode (a penny or a chunk of copper wire), and the lime juice will function as the electrolyte. The lime juice is largely citric acid, which is C6H8O7. The zinc gets oxidized during the electrochemical reaction, so that’s where the oxygen from the citric acid ends up. The hydrogen bubbles up around the copper electrode and escapes into the atmosphere. The carbon is left behind.
I don’t know what a kinda carbon-ish lime with reduced quantities of citric acid would taste like, but I imagine it’s not very good.
Why doesn’t someone do a blind taste test? In the interest of science, of course.
Not me. The pepper spray on pizza test was enough for the year.
I would be happy to do so if you provide the tequila (I have salt, thanks).
Seriously, I doubt you could taste much of a difference - it is not like lime is a simple container of citric acid. Perhaps if you could excise and taste just the areas around the electrodes, but consuming the whole lime or juice, nope.
You will taste the copper, and it is toxic.
Do not consume copper or copper salts.
For those interested in the chemistry, the Wiki has a section with info on the reaction.
If I remember my chemistry, the copper will not react with a weak acid like citric. You will end up with some zinc citrate - which is used in lots of stuff (toothpaste for one) and would be hard to get an overdose from a lime battery.
Ah - you got everything correct but the chemistry incorrect. Oxidizing Zinc means zinc goes from the Zn (0) to Zn (2+) - so Zinc forms zinc citrate. No carbon is left behind.
So the overall reaction is : 3Zn + 2C6H8O7 —> Zn3(C6H5O7)2 + H2
Notice that Copper is not effected.
The “carbon” will be left behind in its unchanged original form, as citrate ion. The difference is that instead of being citric acid (citrate ion with hydrogen ion) it will now be copper citrate, or zinc citrate (or citrates of whatever other metals the electrodes were made from). These will probably taste nasty, and the copper citrate, particularly, will be rather poisonous, but there probably will not be very much of them since most of the lime juice will never get near the electrodes.
In chemistry, oxidation does not necessarily (and does not in this case) mean combination with oxygen, and often does not involve oxygen at all. In this case it means turning neutral metallic zinc or copper into zinc or copper cations (Cu++ or Zn++) which will combine ionically with the negatively charged citrate anions that are left when the acid’s ionically bound hydrogen is removed (as hydrogen gas, as you say). The oxygen in the citric acid is not affected, and remains where it was. (The same goes for the covalently bound hydrogen in the citric anion.)
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Hmm, am77494, who ninjaed me, is probably right to say the copper is not affected. Just zinc citrate and hydrogen is formed. The former will still taste nasty, but not be so poisonous as a copper compound would be.
It will taste like coconut.
if the Professor did it then it will.
It won’t taste like chicken then?
I don’t think it will taste different at all.
You always taste citric acid as an ion because it dissolves in water. So any change in flavor must come from the zinc ions.
Zn 2+ is the same zinc ion found in zinc lozenges that some people think will boost your immune function. I’ve tried them, and can’t say I report any zinc flavoring, even in a lozenge. I can’t imagine that you’d notice anything in a lime/lemon with all the other strong flavors that are present.
Really? I haven’t tried zinc lozenges myself, but I am sure I have read that they taste godawful. Here is a cite to that effect. Google zinc lozenges taste and you will find a lot more.
Your point about citric acid is wrong anyway. NaCl also dissociates into ions as soon as it dissolves in water. By your reasoning, it ought to taste like hydrochloric acid mixed with the taste of sodium ions in water (presumably the soapy bitterness of dilute NaOH). Salt tastes nothing like that.
The typical taste of most acids, including citric and hydrochloric, the sour, acidic taste, comes mainly from the hydrogen cations, not the negatively charged anion part that determines which particular acid it is.
Not a lime, but when we did this in Jr. High, we used an apple. It tasted like battery acid right at the point where the penny was inserted. My friend tasted the other side with the nickle. He said it tasted NASTY!! The rest of the apple tasted like apple, according to the other students.
I could probably be convinced to try the lime for taste, “In the name of science”. I will not do this experiment for a school until late spring. If I remember, I will use a lime and taste it for you-all.
Chemistry never was my strong suit, so I’ll take your word on that. Sometimes you end up with a black film on the copper electrode, if the battery runs long enough. What is that? Carbon? Cupric oxide? Something else?
Other than getting a black film on it, the copper is otherwise unchanged.
Yes, probably cupric oxide. That is black.
I guess my tongue is insensitive to zinc then. My grandparents were big believers in zinc and so I tried several different varieties over the years. Even as an adult, I’ve had some pushed on me by well-meaning friends. Most of them taste like sour candies to me - a lot like Smarties (which have citric acid) or Sweet Tarts (which use malic acid).