Name the reagents used in the following reactions: (i) Oxidation of a primary alcohol to carboxylic acid. (ii) Oxidation of a primary alcohol to aldehyde. (iii) Bromination of phenol to 2,4,6-tribromophenol. (iv) Benzyl alcohol to benzoic acid. (v) Dehydration of propan-2-ol to propene. (vi) Butan-2-one to butan-2-ol.
Alkaline KMnO4 or Acidified K2Cr2O7/KMnO4
PCC (Pyridinium chlorochromate)
Bromine water (Br2/H2O)
Acidified K2Cr2O7 or KMnO4
Concentrated H2SO4
NaBH4 or LiAlH4
Explanation
The context mentions alkaline KMnO4 for oxidation of propan-1-ol (7.17), chromic acid (Na2Cr2O7/H2SO4) for oxidation reactions, bromine in CS2 with phenol, and acid-catalyzed dehydration. For controlled oxidation to aldehyde, PCC is the standard reagent that stops at the aldehyde stage. Bromine water causes electrophilic substitution at all activated positions (2,4,6) of phenol. Catalytic reduction is mentioned in context for converting carbonyl compounds to alcohols.