The managing director of a well-known company on Wall Street thrives

*** State the results that the test would indicate (specify the color of the solution). ***

Well, Benedict's test detects reducing sugars (such as glucose). Benedict's reagent contains blue copper ions (Cu2+) which are reduced to copper (Cu+) in the presence of reducing sugars. These are precipitated as red copper(I) oxide which is insoluble in water.

The color of the solution would be red.



*** State the composition and the properties of the ketohexose derived from fruit jam. ***

I'm not exactly sure what answer this question wants. But anyway...

A ketohexose is a ketone-containing hexose (a six-carbon monosaccharide). In other words, it is a monosaccharide which has a 6 carbon backbone with a ketone group on C2.

Since they have three chiral centers, 8 (2^3 =8) different stereoisomers are possible.

*** Describe the manner in which ketohexose acts as a reducing sugar in the test. ***

When the hemi-acetal or ketal hydroxyl group is free, i.e. it is not locked, not linked to another (sugar) molecule, the aldehyde (or keto-) form (i.e. the chain-form) is available for reducing copper (II) ions. When a sugar is oxidized, its carbonyl group (i.e. aldehyde or ketone group) is converted to a carboxyl group.


Hopes it helps =]

Benedict's reagent is a solution of copper sulfate, sodium hydroxide, and tartaric acid. Aqueous glucose is mixed with Benedict's reagent and heated. The reaction reduces the blue copper (II) ion to form a brick red precipitate of copper (I) oxide. Because of this, glucose is classified as a reducing sugar.

1. Benedict's test detects reducing sugars (such as glucose). Benedict's reagent contains blue copper ions (Cu2+) which are reduced to copper (Cu+) in the presence of reducing sugars. These are precipitated as red copper(I) oxide which is insoluble in water.Therefore the color of the solution would be Red.

2.Ketohexoses is a ketone containing hexose i.e. it consists of six carbon monosaccharides with a keto group ( R-CO_R ) and other carbon atoms consists an OH group and remaining hydrogens. Ketohexoses are soluble in , doesnt have sharp melting points, can char and sweetin taste because of which are added in the jam. 

3. When the hemi-acetal or ketal hydroxyl group is not engaged or locked or linked to another sugar molecule but  free then the aldehyde (or keto-) form (i.e. the chain-form) is available for reducing copper (II) ions. When a sugar is oxidized, its carbonyl group (i.e. aldehyde or ketone group) is converted to a carboxyl group.