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
Nitrite test or dilute urine. In addition, a nitrite test does not detect organisms unable to reduce nitrate to nitrite, such as enterococci, staphylococci ("Staphylococcus saprophyticus"), Acinetobacter, or adenovirus. Nitrite test A nitrite test is a chemical test used to determine the presence of nitrite ion in solution. A common nitrite test can be performed by adding 4 M sulfuric acid to the sample until acidic, and then adding 0.1 M iron(II) sulfate to the solution. A positive test for nitrite is indicated by a dark brown solution, arising from the iron-nitric oxide complex ion. A nitrite test is a standard component