Existence: They are Colourless liquids with pungent smell. The higher members are oily liquids and still higher members are waxy solids.
Solubility : First four members are soluble in H2O that is- HCOOH , CH3 , COOH , C2H5 COOH , C3H7 But as number of Carbon atoms increase , solubility decrease because size of non-polar group increases. Solubility of smaller members is due to formation of Hydrogen bonds.
Boiling points:Boiling points are higher due to formation of hydrogen bonds . As number of Carbon atoms increases , boiling point also increases.
Melting point : Show un-usual behaviour.
Those having odd number of carbon atoms possess low Melting point -
CH3 CH2 COOH = 251k
High Melting point of members with even number of Carbon atoms –