Preparation of chlorobenzene – Sandmeyer’s reaction

Chlorobenzene and bromobenzene can be prepared by treating bezenediazonium chloride with cuprous chloride or cuprous bromide. This reaction is also called Sandmeyer’s reaction. The reaction is named after the Swiss Chemist Traugott Sandmeyer. In this reaction the diazonium group losses the molecule of dinitrogen and it yields chlorobenzene.

What are the methods of preparation of alcohols and phenols ?