Acid-free paper durable acid-free paper. Archival paper is meant to be used for publications of high legal, historical, or significant value. In the USA, such paper must also be approved in accordance with the ANSI standards. The international standard for "permanent" paper is ISO 9706 and for "archival" paper, the standard is ISO 11108. Often, cotton rag paper is used for archival purposes, as it is not made from wood-based pulp. Thus, "archival paper" is sometimes broken down into two categories: Acid-free paper Acid-free paper is paper that if infused in water yields a neutral or basic pH (7 or slightly greater).
Uric acid 1882, the Ukrainian chemist Ivan Horbaczewski first synthesized uric acid by melting urea with glycine. Uric acid displays lactam–lactim tautomerism (also often described as keto–enol tautomerism). Although the lactim form is expected to possess some degree of aromaticity uric acid crystallizes in the lactam form, with computational chemistry also indicating that tautomer to be the most stable. Uric acid is a diprotic acid with p"K" = 5.4 and p"K" = 10.3, thus at physiological pH it predominately exists as the monoionic urate ion. In general, the water solubility of uric acid and its alkali metal and alkaline earth salts is