1. Aldehydes

2. Aldehydes Methanal HCHO Ethanal CH3CHO Propanal C2H5CHO
Butanal C3H7CHO

3. Methanal

4. Ethanal

5. Propanal

6. Butanal

7. Physical properties
Physical state: Liquid, except methanal, which is a gas at room temperature
Boiling points higher than the corresponding alkanes, due to polar +C = O- group, but lower than the corresponding alcohols

8. Physical properties
Short chain aldehydes are soluble in water due to the polar carbonyl group
As the number of carbon atoms in a molecule of the ester increases, solubility in water decreases, while solubility in cyclohexane increases

9. Benzaldehyde
Aromatic aldehyde
Found in almond kernels