A cotton swab is dipped into concentrated hydrochloric acid (producing hydrogen chloride gas) while a second on is dipped into concentrated aqueous ammonia (producing ammonia gas). Both cotton swabs ...

It's pretty common for things to react as liquids and solids, but they can also react as gases. To show this I just need some ...

Guano contains water, ammonia, ulmic, uric ... consisting of the carbonates and phosphates separable by hydrochloric acid from the residue aforesaid ; also sand which is insoluble.

Use a weak acid such as acetic acid and a weak base such as ammonia and after a few times the demonstration ... Universal indicator is flammable and slightly toxic if ingested. Hydrochloric acid is ...