because Orange Juice contains fructose sugar. Fructose is a monosaccharide which gives a positive reaction on benedict's test. changing color indicates that the fructose gave a positive reaction.
I'm not positive on the answer, but its has something to do with the starch reducing the cupric ions of the Benedict reagent, and forming cuprous oxide, Cu2O, which is the yellow-red precipitate that is formed in a positive test The Benedict's test allows us to detect the presence of reducing sugars (sugars with a free aldehyde or ketone group). All monosaccharides are reducing sugars; they all have a free reactive carbonyl group. Some disaccharides have exposed carbonyl groups and are also reducing sugars. Other disaccharides such as sucrose are non-reducing sugars and will not react with Benedict's solution. Starches are also non-reducing sugars. The copper sulfate (CuSO4) present in Benedict's solution reacts with electrons from the aldehyde or ketone group of the reducing sugar to form cuprous oxide (Cu2O), a red-brown precipitate. CuSO4 Cu++ + SO4--
2 Cu++ + Reducing Sugar Cu+
(electron donor) Cu+ Cu2O (precipitate) The final color of the solution depends on how much of this precipitate was formed, and therefore the color gives an indication of how much reducing sugar was present.
(http://www.biosci.ohiou.edu/introbioslab/Bios170/170_2/benedict.htm)
it doesn't change color, it changes other elements color!
Iodine -- it is used as a starch indicator.
The high presence of the common sugar glucose causes the color change from red to brown.
The color is blue.
white turbid solution
if we dissolve a starch in water it forms a colloidal solution and the particle size is much larger to completely dissolve in water
Benedicts solution
place starch solution inside the partially permeable membrane and than partially submerge it a beaker filled with distilled water. after some time, take the tubing out and test the water inside the beaker for starch by adding iodine solution. if the tubing is permeable to starch, the starch would have diffused into the water in the beaker and test positive for starch and turn dark blue. if not, then the water in the beaker would test negative for starch and remain a yellowish brown solution.
since it forms a colloidal suspension, not a proper solution.
there will be a change of color in to blue- black complex
The starch indicator solution will diffuse out of the bag (cell) into the beaker, changing the color of the starch solution to a blue, purple, or black color (assuming that it's iodine). The color of the indicator solution inside the bag will not change, because only the glucose can diffuse into the bag, but the starch cannot diffuse into the bag.
Well what i think is that The water outside of the "cell" will change colors and not the "cell" :D
It depends on how much percentage of of starch solution is to be made. For an example: To make 20% of Starch Solution, you need to pour 20grams of starch powder in 100ml of water. After the powder is dissolved, boil the water. - Ridwan T. Haque International School Dhaka Class of 2009
water.
soluble
1. Place a small amount of starch powder in a test tube filled with cold water 2. Boil it to make a clear solution 3. Once the solution has cooled off, you should put 3 or 4 drops of iodine solution in it. 4. The solution should turn dark blue.
soluble
white turbid solution
The starch solution will turn black, while the distilled water will remain brown, the same colour as the iodine. This is actually because water, normally used as a control, does not contain any starch and as we know, the iodine test is highly specific for the presence of starch hence no colour change other than iodine dissolving in water to form an iodine solution contrary to starch which we know complexes with iodine, to form starch-iodine complex forming the blue-black colour observed
Cooked starch is homogenous. This is by the starch absorbing the water molecules thus creating a consistent solution.
if we dissolve a starch in water it forms a colloidal solution and the particle size is much larger to completely dissolve in water