Our stomach acid is a mixture of different compounds that assist in the breakdown of foods that we ingest. One of the major components is hydrochloric acid (HCl(aq)). We need this acid to help digest our food and kill bacteria that may enter the stomach along with the food. In the absence of food there is an excess amount of acid in our stomachs. This excessive acid production results in the unpleasant symptoms of heartburn and may contribute to the formation of ulcers by irritating the stomach lining. To relieve such symptoms we often use antacids. Antacids are bases (most commonly bicarbonates, carbonates and hydroxides) that are used to neutralize the excess stomach acid.
Fluid magnesia was invented in 1817 by the Irish pharmacist Sir James Murray (1788–1871). Murray built a plant to produce a mixture of magnesium hydroxide in water that he sold for the treatment of a variety of disorders, including heartburn, stomach acidity, bladder and bowel problems, and "female problems." He said that the liquid mixture was much more effective than powdery magnesium hydroxide which had previously been used for the same purposes. In 1880, New York chemist Charles Henry Phillips (1820–1882) invented the name "milk of magnesia" and opened his own factory for producing the product. The name Phillips Milk of Magnesia is one of the oldest and best known over-the-counter medicines ever made in the United States.
Phillips Milk of Magnesia is a combination of magnesium salt and such as magnesium chloride (MgCl2), with sodium hydroxide (NaOH). The magnesium chloride and sodium hydroxide react to produce sodium chloride and magnesium hydroxide, which settles out of solution as a precipitate. Here the manufactures would separate the sodium chloride and magnesium hydroxide. They would be left with magnesium hydroxide as would leave the sodium chloride as a waste product .This is classified as a Double Displacement reaction.
MgCl2(aq) + 2NaOH (aq) →
References: http://www.rxlist.com/script/main/art.asp?articlekey=87811 Chemistry 104: Analysis of Antacid Tablet. Retrieved Oct 31, 2012, fromhttp://www.chem.latech.edu/~deddy/chem104/104Antacid.htm BookRags.com | Homework Help, Book Summaries, Study Guides, Essays, Lesson Plans, & Educational Resources.Retrieved November 4, 2012, from http://www.bookrags.com/research/magnesium hydroxide-chmc/ Shakhashiri, B Heartburn FAQ - How many people are afflicted with GERD?.Retrieved November 4, 2012, from http://heartburn.about.com/library/bl_gerdafflicted.htm