aldehydes and ketones

Question 1

hydrations of carbonyls

Answer 1

• water acts as a nucleophile, C with partial + charge acts as electrophile
• fast reaction

Question 2

equilibrium constant for hydrations

Answer 2

Khdr is equilibrium constant for [hydrate] / [carbonyl]

Question 3

factors in equilibrium constants for hydrations

Answer 3

• inductively donating alkyl groups (e.g. in ketones) stabilize partial + charge on C by pulling electrons toward it–carbonyl favored
• electron-withdrawing groups (e.g. electronegative atoms) pull electrons away from C, destabilizing it–hydrate favored

Question 4

stability of aldehydes vs ketones in hydration

Answer 4

• small aldehydes: large Khdr; hydrate favored
• ketones and large aldehydes: small Khdr; carbonyl favored

Question 5

carboxylic acid derivatives

Answer 5

• carbonyl group bound to electronegative heteroatom
• reactivity depends on electronegativity of heteroatom!

Question 6

stability of carboxylic acid derivatives

Answer 6

• amides and esters are more stable than aldehydes/ketones (donate electrons to stabilize C)
• acid anhydrides and carboxylic acid chlorides are less stable than aldehydes/ketones (pull electrons away from C)