1. Fructose is a ketose sugar but gives a positive reaction with Fehling's reagent because the base in the reagent shifts the double bond to convert the ketone group into an aldehyde, allowing it to react. 2. The iodine test is used to indicate the completion of starch hydrolysis by acid. 3. Acid hydrolysis of starch is faster than enzymatic hydrolysis. 4. Amylose gives a positive iodine test and negative Fehling's test due to its linear structure without an aldehyde or ketone group that could react with Fehling's reagent.