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Discussion:

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Three solutions, S1, S2 and S3 were given and its constituents was unknown. It was told that one solution contained glucose, one contained another carbohydrate and the last contained protein. Therefore three tests: Benedict’s for the reducing sugar glucose, Non -reducing sugar test for the carbohydrates and the Biuret’s for protein was carried out on all three solutions provided. The solutions were determined according to the positive results it gave to which test performed.

The Benedict’s test was carried out on all three solutions. 2cm(cubed) of S1, S2 and S3 were placed to respective test tubes, an equal volume of Benedict’s solution was added and the mixture was thoroughly shaken and brought to a boil. Solutions S1 and S2 showed no colour change whereas solution S3 was discolored from its initial blue coloration, turning green, then yellowish and finally a brick red precipitate. Benedict’s solution contains copper sulfate. Reducing sugars reduce soluble blue copper sulfate containing copper(II) ions (Cu2+) to insoluble red brown copper oxide containing copper(I). The latter is seen as a precipitate. This test is semi-quantitative, meaning that an approximation of the amount of reducing sugar present is possible. The final precipitate will either appear green to yellow to orange to brick red according to the amount of reducing sugar present.

Next, the non-reducing sugar test was performed on each solution. 2cm (cubed) of S1 was measured out into a test tube and 1c em(cubed) of dilute hydrochloric acid was added. The solution was neutralized with sodium hydrogen carbonate and then the Benedict’s test was performed. This was repeated for S2 and S3. It was observed that a foamy substance was produced when HCL was added to S1, no colour change was seen for S3 whereas S2 produced a brick red precipitate when the Benedict’s test was performed. A disaccharide can be hydrolyzed to its monosaccharide constituents when boiled with the...