Which is more stable among

phenol and phenoxide ion ?

phenol and phenoxide ion both are stabilized by resonance. In case of phenol the lone pair on oxygen atom get delocalize over the ring and if we look into the resonance structures of phenol there is a charge seperation i.e. there is positive charge on oxygen atom and negative charge on the ring carbons. This type of resonance structures have small contributions to the hybrid in stabilizing the compound. Whereas in case of phenoxide ion, the negative charge on the oxygen atom get delocalize and no such charge separation take place. Therefore the resonance structures of phenoxide ion has more contributions toward the hybrid in stabilising the phenoxide ion. Hence phenoxide ion is more stable than phenol.