How to dispose of Sulfuric Acid

chemicalsdisposalsafety

I have about 30 ml of leftover Sulfuric acid. There is a similar thread on this board suggesting ways to dispose of it. They involve adding baking soda after adding the sulfuric acid to water. However, the MSDS sheet for sulfuric acid contains the following statement which scares me:
"A violent exothermic reaction occurs with water."

Any suggestions please.

Best Answer

As my high school chemistry instructor made us learn:

Do as you oughta - add acid to water.

If you add water to acid, the reaction dynamics work out badly and you get the MSDS warning - the water boils, this spits acid solution all over, and is dangerous.

If you add acid to water, the reaction dynamics work in a more favorable fashion, and nothing exciting happens as you dilute the acid.

To further enhance safety, you can use cold water and chill the acid, though this is a bit more than is really needed.

Gloves and eye protection are always advisable.