Compusi carboxilici:
Reactia cu metale active: 

H-COOH + K ->
H-COOH + Mg ->


Răspuns :

HOOCH + K ---> HCOOK + 1/2 H2    formiat de potasiu
2 HCOOH + Mg ---> (HCOO)₂Mg + H2    formiat de magneziu