Litmus "Lecanora tartarea" (Norway, Sweden), "Variolaria dealbata", "Ochrolechia parella", "Parmotrema tinctorum", and "Parmelia". Currently, the main sources are "Roccella montagnei" (Mozambique) and "Dendrographa leucophoea" (California). The main use of litmus is to test whether a solution is acidic or basic. Wet litmus paper can also be used to test for water-soluble gases that affect acidity or alkalinity; the gas dissolves in the water and the resulting solution colors the litmus paper. For instance, ammonia gas, which is alkaline, turn the red litmus paper blue. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or
Acidity function aqueous solution of pH 0. The actual reactive species are different in the two cases, but both can be considered to be sources of H, i.e. Brønsted acids. <br>The hydrogen ion H "never" exists on its own in a condensed phase, it is always solvated to a certain extent. The high negative value of "H" in SbF/HSOF mixtures indicates that the solvation of the hydrogen ion is much weaker in this solvent system than in water. Other way of expressing the same phenomenon is to say that SbF·FSOH is a much stronger proton donor than HO. Acidity function An acidity