identify ketone using 2,4- dinitrophenylhydrazine test

Question 1

do ketones give positive test with Fehlings and Tollens reagent?

Answer 1

no because ketones don’t have free aldehydes groups that can be oxidized to carboxylic acid which can be detected by change in color.

Question 2

can you use 2,4DNPH regents to test sugar in the urine of a diabetic patient?

Answer 2

yes it can be used to test for the presence of reducing sugar such as glucose.

Question 3

give a few characteristic properties of 2,4 dinitrophenyl hydrazine

Answer 3

yellow or orange in color, insoluble in water, soluble in organic solvent such as ethanol,polar compound , organic compound

Question 4

what is the formula for 2,4 dinitrophenyl hydrazine

Answer 4

C6H6N4O4

Question 5

what is the formula for fructose

Answer 5

C6H12O6

Question 6

a fructose is aldehyde or ketone

Answer 6

fructose is ketone

Question 7

what is the color of precipitate when fructose reacts with 2,4 dinitrophenyl hydrazine

Answer 7

orange or yellow precipitate is formed