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
Alkalinity carbonate ion. At equilibrium, the water contains a certain amount of alkalinity contributed by the concentration of weak acid anions. Conversely, the addition of acid converts weak acid anions to CO and continuous addition of strong acids can cause the alkalinity to become less than zero. For example, the following reactions take place during the addition of acid to a typical seawater solution: It can be seen from the above protonation reactions that most bases consume one proton (H) to become a neutral species, thus increasing alkalinity by one per equivalent. CO however, will consume two protons before becoming a