Nitrate test to 2.5 micrograms and a concentration of 1 in 25,000 parts. Devarda's alloy (Copper/Aluminium/Zinc) is a reducing agent. When reacted with nitrate in sodium hydroxide solution, ammonia is liberated. The ammonia formed may be detected by its characteristic odor, and by damp red litmus paper's turning blue, signalling that it is an alkali — very few gases other than ammonia evolved from wet chemistry are alkaline. Aluminium is the reducing agent in this reaction that will occur. Diphenylamine may be used as a wet chemical test for the presence of the nitrate ion. In this test, a solution of diphenylamine
SAT Subject Test in Chemistry of 110. The College Board's recommended preparation is a one-year college preparatory course in chemistry, a one-year course in algebra, and experience in the laboratory. However, some second-year algebra concepts (including logarithms) are tested on this subject test. Given the timed nature of the test, one of the keys of the mathematics that appears on the SAT II in Chemistry is not the difficulty, but rather the speed at which it must be completed. Furthermore, the oft-quoted prerequisite of lab-experience is sometimes unnecessary for the SAT Subject Test in Chemistry due to the nature of the questions concerning experiments; most