Name the reagents used in the following reactions:
i. Oxidation of a primary alcohol to carboxylic acid.
ii. Oxidation of a primary alchol to aldehyde.
iii. Bromination of phenol to 2,4,6-tribromonophenol.
iv. Benzyl alcohol to benzoic acid.
v. Dehydration of propan-2-ol to propene.
vi. Butan-2-one to butan-2-ol.

Explanation

(i) Acidified potassium dichromate or, neutral, acidic or alkaline potassium permanganate (followed by hydrolysis with dil. `H_(2)SO_(4)`)
(ii) Pyridinium chlorochromate `(P C C),C_(5)H_(5)NH^(+)CrO_(3)Cl^(-)` in `CH_(2)Cl_(2)`.
or Pyridinium dichromate `(PDC)," "(C_(5)H_(5)overset(+)(NH))_(2)Cr_(2)O_(7)^(2-)` in `CH_(2)Cl_(2)`.
(iii) Aqueous bromine, i.e., `Br_(2)//H_(2)O`.
(iv) Acidified or alkaline potassium permanganate (followed by hydrolysis with dil. `H_(2)SO_(4)`)
(v) 85% `H_(2)SO_(4)` at 440K.
(vi) `Ni//H_(2)` or `NaBH_(4)` or `LiAlH_(4)`.