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Describe laboratory method for preparation of glucose . Write the reaction that indicates the presence of - CHO group in glucose . |
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Answer» Solution :Laboratory method for the preperation of glucose : Glucose can be prepared by boiling sucrose with dilute hydrchloric acid or dilute sulphuric acid for two hours . Sucrose gives glucose and fructose on hydrolysis . `underset("Sucrose")(C_(12)H_(22)O_(11))+H_(2)O overset(H^(+))underset(("dil. HCl"))rarr underset("Glucose")(C_(6)H_(12)O_(6))+underset("Fructose")(C_(6)H_(12)O_(6))` In order to separate glucose from fructose , alcohol during COOLING . Glucose CRYSTALLIZES out first as it is insouble in alchol . While fructose is soluble in alcohol. while fructose is soluable , so it still rmaions in the solution then , the solution is fitered to obtain CRYSTALS of glucose . ,brgt ACTION of BROMINE water on glucose : , The oxidation of glucose with bromine water forms gluconic acid . This indicatyes the presence of aldehyde group . 
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