Carbonyls Flashcards
What is a carbonyl bond?
C=O
Describe a carbonyl bond.
Carbonyl bonds form sigma and pi bonds in the same way that C=C bonds do, with the overlap of p orbitals. They are polar due to the electronegativity of oxygen.
WHat is the shape around a C atom in a carbonyl bond?
Trigonal planar with a 120 degree bond angle.
What is the functional group of an aldehyde?
-CHO
What is the functional group of a ketone?
-CO-
What is the functional group of an ester?
-COO-
What is an acyl chloride?
A carboxylic acid with a chlorine atom instead of an OH group
What is the functional group of an acyl chloride?
-COCl
What is Brady’s reagent?
2, 4- DNPH dissolved in phosphoric acid and methanol
Describe the appearance of Brady’s reagent.
A clear orange solution.
How does Brady’s reagent react with carbonyls?
Carbonyl compounds form an orange precipitate (a 2,4-DNPH derivative) in Brady’s reagent.
What is the test for a carbonyl compound?
Brady’s reagent.
How can 2,4-DNPH derivatives be used to identify carbonyls?
They have varying melting points.
What is the test for aldehydes?
Tollens’ reagent.
What is tollens’ reagent?
Ammoniacal silver nitrate.
How does tollens’ reagent react with aldehydes?
It oxidises them to carboxylic acids, and the reduced silver deposits on the test tube in a silver mirror.