I know $\ce{HCl}$ and $\ce{H2SO4}$ acid of concentration 17 M is dangerous and corrosive, but I wonder can we dilute these acids to the extent that they become safe to touch?

If yes, then what should be the molarity of that safe acid?


closed as off-topic by Todd Minehardt, MaxW, airhuff, Jon Custer, Mithoron Jun 6 at 15:04

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Personal medical questions are off-topic on Chemistry. We can not safely answer questions for your specific situation and you should always consult a doctor for medical advice." – Todd Minehardt, Jon Custer
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Seems like the old joke about a horseshoe. Blacksmith - "Hot eh?" Tinhorn - "Nope, it just doesn't take long to look at a horseshoe." $\endgroup$ – MaxW Jun 6 at 4:18
  • 1
    $\begingroup$ I believe $10^{-8}\rm M$ is fairly safe. $\endgroup$ – Ivan Neretin Jun 6 at 4:57

According to the Globally Harmonised System (GHS), hydrochloric acid with a concentration of c ≥ 25 % and sulfuric acid with a concentration of c ≥ 15 % are labelled "causes severe skin burns and eye damage" (H314) and are classified based on standard animal test data in skin corrosion Sub-category 1B ("Corrosive responses in at least one animal following exposure > 3 min and ≤ 1 h and observations ≤ 14 days"). "Skin corrosion refers to the production of irreversible damage to skin; namely, visible necrosis through the epidermis and into the dermis occuring after exposure to a substance or mixture."

Hydrochloric acid with a concentration of 10 % ≤ c < 25 % and sulfuric acid with a concentration of 5 % ≤ c < 15 % are labelled "causes skin irritation" (H315) and are classified based on standard animal test data in skin irritation Category 2. "A substance is irritant to skin when it produces rversible damage to the skin following its application for up to 4 hours."

Concentrations well below these values may be considered safe for the exposure of skin to the substance.

Note that the natural skin surface pH is below 5.

  • 2
    $\begingroup$ It seems to imply that HCl with c = 3% is claimed to be safe, even if applied for up to 4 hours. Somehow I don't buy that, though, and I'm not much of a security freak, to put it mildly. $\endgroup$ – Ivan Neretin Jun 6 at 9:37

Not the answer you're looking for? Browse other questions tagged or ask your own question.