Alcohols, Phenols and Ethers Part 1

In the electrophilic substitution reaction, phenol gives ortho and para substituted product in which para is the major product. The electrophilic substitution reaction of phthalic anhydride with phenol is taking place at para position of the phenol. Allthe given molecules have free para position except in p-cresol.
Hence, it does not give colour of phthalic anhydride.
The reaction is as follows :