20. Sudan III is used to test for A. cellulose.
B. fats and oils.
C. glucose.
D. protein.
E. starch.

Lipid tests

Sudan III is a red fat-soluble dye that is utilized in the identification of the presence of lipids, triglycerides and lipoproteins. The Reaction: Sudan III reacts with the lipids or triglycerides to stain red in colour.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.