The following compounds are phenol derivative. If number of phenol derivative = x . Number of phenol derivative gives +ve test with NaHCO₃ = y .
Then find the value of x + y .

x = a,b,c,d,e,f; y = b,e.

All are phenol derivatives due to OH connected to benzene. Greater the acidity fast the reaction with bicarbonate. Since Acidity increases if 
1. More minus I effect is present.
2. The resulting ion is stable.
3. The proton is donated fast.
4.Conjugate base must be stable.

The general order of acidity is,
RCOOH>Phenol>Water>Alcohols>yne>ene>ane.