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
GRE Chemistry Test GRE Chemistry Test The GRE subject test in chemistry is a standardized test in the United States created by the Educational Testing Service, and is designed to assess a candidate's potential for graduate or post-graduate study in the field of chemistry. It contains questions from many fields of chemistry. 15% of the questions will come from analytical chemistry, 25% will come from inorganic chemistry, 30% will come from organic chemistry and 30% will come from physical chemistry. This exam, like all the GRE subject tests, is paper-based, as opposed to the GRE general test which is usually computer-based. It contains