What is H2SO4 AND H2O

Anecdote below aside, the equation is H2SO4 + H2O -> HSO4- + H3O+ ---- It depends on whether you add Acid to Water, or Water to Acid. Though Sulfuric Acid is highly soluble in water, if you add water to concentrated Sulfuric Acid it can boil, spit and splash out of its container. If you've never had burns from concentrated Sulfuric Acid, trust me when I say you never want to experience it. There is nothing quite like seeing the skin literally melt from your body, not to mention the pain.

It is therefore preferable to add the Acid to water in small amounts until the necessary amount of dilution is achieved. In all cases, be sure to wear a long sleeve shirt, eye protection (preferably a facial mask) and breather, plus chemical gloves. If you aren't near running water, ensure that you have a gallon of fresh water available for flushing any areas of your body that may accidentally come in contact with the acid. I'd also recommend wearing a hat.

In my case, I was wearing a ballcap, heavy long sleeve denim shirt, but since I was only moving the bottle, I wasn't wearing gloves or facial protection. The bottle slipped out of my hand and hit flat on the bottom when it hit the floor, causing the acid to spurt out of the spout. The cap wasn't on tight and had come loose. It is a miracle that it didn't get into my eyeball, though it did get the right side of my face, under my chin, all around my eye, and part of my ear. It completely destroyed and burned the denim shirt I was wearing, and caused a 3rd degree burn on my wrist. The ballcap saved me from having to shave my had also - if it had hit my hair it would've destroyed it as well.

The only thing that kept my injuries to a minimum was that I've worked in military and industrial areas all my life, and instinctively moved toward the laundry tub and water to flush out the acid. I had water flushing it within 30 seconds. According to the plastic surgeon I consulted, it's the only thing that kept the burns from being much worse. As it is, you can't tell except for lighter skin pigmentation. The worst scar is on my wrist where it literally burned down to the muscle.

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Dilution, as long as you mix them properly