how can we distinguish among different acids?

Question

different acids are placed in many bootles without any label so how we distinguish among them in short period of time?

Answer 1

I am assuming you are referring to the common acids like say sulfuric, nitric, hydrochloric and acetic.

Sulfuric is easy, put a drop on a paper towel the drop will turn black.

Acetic you can (carefully) smell. I did this once and got vapor lock. I held the bottle right up to my nose, just like they tell you not to. Once burned, twice shy. Hold it at arms length and smell for the scent of vinegar.

Nitric is easy too, just heat a little bit and you should see a brown cloud of Nitrogen dioxide evolving off. Once again don’t get carried away just a few drops in an Erlenmeyer flask is fine. Wear your safety glasses.

Hydrochloric is a bit harder. I like to do the flame test. Place a piece of aluminum foil in a test tube. Cover it with the hydrochloric. Wave a red-hot ember over the top of the tube. You should get a nice popping sound; some times the wood split will catch fire. Best to place the tube in a rack first, sometimes the popping sound will surprise you and splash HCl all over the place.