Sulphuric acid

Sulphuric acid was an acidic compound. It rained sulphuric acid on Kaalann. (GAME: City of the Daleks) The seas of 16 Alpha Leonis One were made of sulphuric acid. Agent Yellow freed sulphur compounds which combined with water to form sulphuric acid. (PROSE: Eternity Weeps) The Eleventh Doctor recommended using it to dissolve the TARDIS's translation circuits. (COMIC: Sticks and Stones)