Carboxylate
![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/8e/Carboxylate-resonance-hybrid.png/220px-Carboxylate-resonance-hybrid.png)
A carboxylate is the conjugate base of a carboxylic acid, RCOO− (or RCO−2). It is an ion with negative charge. Carboxylate ions are made when a carboxylic acid loses a hydrogen ion. Such acids usually have pKa of less than 5, meaning that many bases, such as sodium hydroxide or sodium bicarbonate can remove the hydrogen ions from them.
RCOOH + NaOH → RCOONa + H2O
Examples
Some examples of carboxylates include;
- Formate ion, HCOO−
- Acetate ion, CH3COO−
- Methanetetracarboxylate ion, C(COO−)4
- Oxalate ion, (COO)2−