it produces a brick/dark red stain.
because it want to show that Sudan iv is soluble in water n not soluble when there is lipid presence . From there you can make lipid as your responding variable
The sudan dye is a lipid itself, therefore you have a lipid layer interacting with another lipid.
The chemical Sudan IV is not soluble in water; it is, however, soluble in lipids. Therefore to test for the presence of lipids in a solution you will use a Sudan IV Test. In this test dark red Sudan IV is added to a solution along with ethanol to dissolve any possible lipids. If lipids are present the Sudan IV will stain them reddish-orange, giving a positive test.
Sudan IV is a diazo dye for staining lipids, lipoproteins, and triglycerides. It is used in Sudan staining, wherein it attaches to the fats chemically.
Sudan IV is only soluble in certain solvents.
If no lipids are present, the red dye will sink to the bottom of the test tube. Sudan (iv) is not soluble in water but soluble in lipid.
I think its red....
We just did a lab on this in my bio class.The Sudan test uses Sudan IV reagent. If a lipid or fat is present, red globs of fat will appear at the top of the solution. If not, there won't be a reaction.The translucence test is when a drop of liquid is placed on an unglazed paper. Water will dry up and leave the paper crinkly. An oil or fat will spread out, and leave a stain, not really drying, and making the paper look translucent.
Like lipids, the chemical Sudan IV is not soluble in water; it is, however, soluble in lipids. Therefore to test for the presence of lipids in a solution you will use a Sudan IV Test. In this test dark red Sudan IV is added to a solution along with ethanol to dissolve any possible lipids. If lipids are present the Sudan IV will stain them reddish-orange, giving a positive test.
Sudan dye is lipid -soluble dye, thus, it will turn any lipids to red. It mixes with it.
There is a colour change because like fats, Sudan IV is not soluble in water. So when you add Sudan IV to lipids, it will break down therefore the chamical reaction that takes place is the colour change.
for me, i think the uncoated paper test is more sensitive than Sudan iv test. This is because Sudan iv test can only soluble in certain solvent thus make it harder to define either the solution that is tested is really have lipid in it although there is not. The uncoated paper test can show if there is lipid the the solution if greasy transparent spot comes out from the uncoated paper.