Aldehyde
Reduction
Aldehyde + reudicng agent -> primary alcohol
The reagents used are NaBH4/LiAlH4 and in dry ether
Examples
Nuclephillic Addition
Aldehyde + HCN -> hydroxynitrile
Created by
Primary alcohol + oxidising agent -> aldehyde
The reagents used are Acidified Potassium Manganate or Acidified Potassium Dichromate
Potassium dichromate changes from Orange to Green
Condition: heated in reflux
Potassium Manganate changes from Purple to Colorless
Condensation
Aldehyde + 2,4-DNPH -> Deep orange precipitate + water
Deep orange precipitate can be observed
Oxidation
With KMnO4
With tollent's regeant
with fehling regeant
Iodoform test
Potassium Manganate changes from purple to colourless
Aldehyde + KMnO4 -> Carboxylic Acid
Condition: KMnO4 is acidified and under reflux
Aldehyde + ammoniacal silver nitrate -> Ammonium Carboxylate + Ag + Water + Ammonia
silver mirror precipitate can be observed.
Aldehyde + Cu2+ -> Carboxylic Acid + Cu2O
Red precipitate can be observed
Aldehyde + I2 -> Sodium salt + Iodoform
Yellow precipitate can be observed
This only works for ethanal