What is the chemical composition of lime?and is it suitable for human comsumption?

Question

What is the chemical composition of lime?and is it suitable for human comsumption?

Answer 1

Lime is calcium oxide (CaO), and it will react with water to form the strong base calcium hydroxide (Ca(OH)2), so it should not be eaten.

Answer 2

The citrus fruit is suitable for human consumption, the chemical is not.

Answer 3

Lime (from limestone) is a mineral composed of different calcium salts, the majority being calcium carbonate CaCO3 (calcium oxide, and hydroxide are present as well).  Many buildings are made of limestone, and cement is composed of mainly CaO (from heating lime) before mixing with other materials, and setting into concrete.  If you've ever ingested a Tum (an antacid) or eaten a piece of blackboard-chalk for an upset stomach you'd realize it's perfectly safe (of course, not in a mega dose) to ingest.  Digestively, Ca(OH)2 is not nearly as harmful than other strong bases.  Unfortunately, people continue to believe everything they hear; especially when it comes to chemical-safety.  There are famous examples: "dangerous" polychlorinated biphenyls, and the belief that methylene chloride is toxic and flammable.  I could go on, and on with various "chemical-scares" this country has endured (eg. cake mix scare of 1984, low-profit soda company sued for benzoic acid preservative "decarboxylating to benzene", etc.).  These are entirely different topics, but I'm trying to emphasize all chemicals aren't bad.  There are of course truly carcinogenic/fatal examples (carbon tetrachloride, dimethyl mercury), but CaCO3 and Ca(OH)2 in moderation certainly aren't going to kill you.  Metal hydroxides from period II (alkaline earth metal hydroxides) are OK to ingest.  In fact, Mg(OH)2, magnesium hydroxide (a period II metal hydroxide), is sold over-the-counter as "Milk of Magnesia" for its laxative effects.  However, if you ingested NaOH or KOH (period I metal hydroxide) in a similar quantity, the most likely diagnosis would be death (or some other serious damage) via saponification. As for your dental health, I wouldn't recommend chewing on a piece of limestone, or any hard rock for that matter.