quailmaster has
pretty much covered it. Any further questions?
Note that CCl4 solvent is used (in the 1st step) if
electrophilic aromatic substitution of only one Cl to the para
position is desired. If aqueous solvent is used, disubstitution /
dichlorination of Cl to both the para and the available ortho
position will be achieved, due to the strongly polar water molecule
inducing a stronger temporary dipole in the non-polar halogen
molecule.
And in case you're wondering why (in step 2) you need to
deprotonate the phenolic group, it is to generate a sufficiently
strong nucleophile. (If not for the negative formal charge on
the O atom of the phenoxide ion, the O atom of phenol actually
has a partial positive charge on its resonance hybrid, due to
delocalization of the O atom's lone pair into the benzene ring,
which makes it an unfeasibly weak nucleophile. Hence,
deprotonation by NaOH is necessary.)
