[Professor Gaarder (OP)]

Um, hi.

I have a question about Hydrochloric Acid. I was in science class about a month ago and I think I may have spilled some HCl on my hand. Now, on my palm, a clear blemish has popped up where I thought I spilled it. It's kind of yellowish, but no signs of pus inside.

Anyone know what's wrong?

[Bored chemist]

HCl stings a bit at the time but I doubt it would be producing any effect a month later- it's too small a molecule to stay around.
I can't think of any reasons for blisters on the palms of teenagers but perhaps you ought to take it to the doctor.

[Professor Gaarder (OP)]

I forget, is the HCl bond covalent or ionic?

[Make it Lady]

Ionic.

This could be a chemical burn but the time lapse is too long.

[Professor Gaarder (OP)]

I don't know, a month is just a rough estimate.

But it doesn't seem like a burn.

[Make it Lady]

Mild acid burns can just look like a yellow mark. You may find the skin goes hard and peels off later. That is if it was the acid. Have you been smoking?

[Professor Gaarder (OP)]

smoking? I'm 14 . . .

no.

but yes, the skin is kind of hard and is yellowish. And I'm 99% certain that was where the HCl ended up.

[Bored chemist]

Except in the case of HF (and you would really know about that) a day is too long for an acid burn to show up; an hour before you noticed it would be odd. "Pretty near imediate" is my experience.

Incidentally, HCl is a covalent gas, but it dissolves in water to form essentially H+ and Cl- ions.

[lyner]

It sounds as if you got an infection in there. If it were me, I'd pop the blister and wash it out. But that's not what a Dr would tell you to do.

[Professor Gaarder (OP)]

well, what doctors tell me can be pretty painful, but I'm not even sure it can be popped.

I'll post a picture in a day or so (damn digital camera wont work)

[chris]

Are you sure it was HCl and not nitric acid? I dropped nitric acid on my hand once and developed a yellow patch like that you describe. I suspect that, in that case, the pigmentation was an oxidation product resulting from the reaction between the acid and proteins in the skin.

[another_someone]

I think the argument Bored Chemist put forward about the time span makes it less likely that it is a direct oxidation reaction.

My suspicion is that the blistering is just part of the healing process, where the newer skin is causing the damaged top layer of skin to detach.

[lightarrow]

Um, hi.

I have a question about Hydrochloric Acid. I was in science class about a month ago and I think I may have spilled some HCl on my hand. Now, on my palm, a clear blemish has popped up where I thought I spilled it. It's kind of yellowish, but no signs of pus inside.

Anyone know what's wrong?

Sure it was not HNO3? That makes skin yellowish (and plastic-like) after some hours.

[lightarrow]

I forget, is the HCl bond covalent or ionic?

The percent ionic character of HCl is less than 26% so it's more covalent than ionic.

http://www.chem.unc.edu/undergrads/2006spring/chem11-2_morse/Percent_Ionic_Character.pdf

[lightarrow]

Are you sure it was HCl and not nitric acid? I dropped nitric acid on my hand once and developed a yellow patch like that you describe. I suspect that, in that case, the pigmentation was an oxidation product resulting from the reaction between the acid and proteins in the skin.

Yes, it could be a nitrification of the -OH sites. If the process were brought at high levels, the skin could become flammable (or...no, explosive not...I hope so!  [])