单词 | benedict's solution |
释义 | Benedict's solutionBen·e·dict's solutionB0185700 (bĕn′ĭ-dĭkts)Benedict's solutionorBenedict's reagentBenedict's solutionBenedict's solution,deep-blue alkaline solution used to test for the presence of the aldehydealdehyde[alcohol + New Lat. dehydrogenatus=dehydrogenated], any of a class of organic compounds that contain the carbonyl group, , and in which the carbonyl group is bonded to at least one hydrogen; the general formula for an aldehyde is RCHO, where R is hydrogen ..... Click the link for more information. functional group, −CHO. The substance to be tested is heated with Benedict's solution; formation of a brick-red precipitate indicates presence of the aldehyde group. Since simple sugars (e.g., glucose) give a positive test, the solution is used to test for the presence of glucose in urine, a symptom of diabetes. One liter of Benedict's solution contains 173 grams sodium citrate, 100 grams sodium carbonate, and 17.3 grams cupric sulfate pentahydrate. It reacts chemically like Fehling's solutionFehling's solution , deep-blue, alkaline solution used to test for the presence of aldehydes (e.g., formaldehyde, HCHO) or other compounds that contain the aldehyde functional group, -CHO. ..... Click the link for more information. ; the cupric ion (complexed with citrate ions) is reduced to cuprous ion by the aldehyde group (which is oxidized), and precipitates as cuprous oxide, Cu2O. Benedict's solution[′ben·ə‚diks sə′lü·shən]Benedict's solutionBenedict's solution[ben´ĕ-dikts]Benedict's solution(bĕn′ĭ-dĭkts) |
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