كس امك وارم
discussion abut bial test ??
Bial's test is used to determine the presence of a pentose sugar. For example, the sugar ribose would turn green (positive) and the sugar glucose would turn brown or yellow (negative). Nucleic acids (DNA and RNA) both contain a suger. RNA contains ribose, so it should have a positive orcinol test. DNA contains deoxyribose, which should have a weak reaction, yielding what appears to be a negative result.
Glucose, fructose, maltose, sucrose, lactose, and starch are carbohydrates that would likely test positive in Molisch, Benedict's, Barfoed's, Seliwanoff's, Bial's, and fermentation tests. These carbohydrates are commonly used in biochemical testing due to their distinct reactivity with the specific reagents in each test.
Dehydration of monosaccharide to form furfural http://www.harpercollege.edu/tm-ps/chm/100/dgodambe/thedisk/carbo/bial/bials.htm Formation of furfural/orcinol complex http://61.19.145.8/student/m5year2006-2/502/group08/rooms5.html