how to determine which compound reacts with NaOH (eg.carboxylic acid,phenol) also same for NaHCO_​3

Dear Student,

The compounds which can react with NaOH and NaHCO₃ can be determined by the acidity of the compounds. 
Most acids react with NaOH as it is a strong base but most acids do not completely neutralize NaHCO₃ because it is weak in nature.
The lower the pK_a, the stronger the acid. Similarly, the lower the pK_​b, the stronger the base.

For the given example of carboxylic acid and phenol:

Carboxylic acid is a stronger acid than phenol because the negative charge in the conjugate base is more dispersed than in conjugate base of phenol, due to the presence of two O atoms. Also, in the resonance structures, in carboxylic acids, the negative charge is present on the O atoms whereas in phenol, the negative charge is present on the electropositive carbon as well, thus decreasing the stability.

NaOH reacts with both carboxylic acid and phenol because it is a strong base.
But, NaHCO₃ reacts with only carboxylic acid and not phenol because both phenol and bicarbonate are weak in nature.


Reactions:

With NaOH:



With NaHCO₃:





Phenol + NaHCO₃   $\to$ No Reaction



Regards