The biuret test is a chemical test used for detecting the presence of peptide bonds. In a positive test, a copper(II) ion is reduced to copper(I), which forms a complex with the nitrogens of the...
Because it is a so-called nonreducing sugar in neutral or alkaline solution. In acidic solution however (e.g. in sugar containing limonades), the nonreducing di-saccharide sucrose is quit easily...