| Test and solution contents | Tested for | Reaction | Result |
| Molish’s Test Alpha napthol in 95% EtOH | Carbohydrates | With the addition of c. H2SO4 the carbohydrates are dehydrated in to respective aldehydes and with a phenol, a dye is formed. | Purple ring at the interface at the two phases.
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| Benedict’s Test CuSO4, NaOH and Tararic acid | Reducing mono saccharides and disaccharides | The sugars are oxidized and Cu2+ is reduced to Cu2O | A brick red ppt |
| Seliwanoff’s Test Resorcinol and c. HCl or H2SO4 | Ketoses | Based on the fact that Ketoses are dehydrated faster than aldoses | Red solution |
| Iodine Test I2 in KI | Starch | A complex is formed. The other polysaccharides may give colors including blue or red. | Formation of a blue black complex |
| Bial’s Test Orcinol, HCl, FeCl3 | Pentoses | The pentose will be dehydrated to form furfural. | Blue colour solution formed |
| Tollen’s Test Ammonical AgNO3 | Sugars with aldehyde group | [Ag(NH3)2]+ + e- → Ag↓ + 2 NH3 RCHO+3 OH- → RCOO-+2H2O+ 2 e-
| Formation of a silver mirror |
| Barfoed’s Test Cu2+ in acetic acid | Monosaccharides | Disaccharides may also react, but very slowly. RCOH+2Cu2++2H2O→RCOOH+Cu2O↓+4H+ | A brick red ppt |
http://www.harpercollege.edu/tm-ps/chm/100/dgodambe/thedisk/carbo/yback9.htm
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