Describe a simple chemical test that could be used to distinguish between members of each of the

Question:

Describe a simple chemical test that could be used to distinguish between members of each of the following pairs of compounds:
(a) 4-Chlorophenol and 4-chloro-1-methylbenzene
(b) 4-Methylphenol and 4-methylbenzoic acid
(c) 4-Methylphenol and 2, 4, 6-trinitrophenol
(d) Ethyl phenyl ether and 4-ethylphenol