Explanation

(b)
In presence of NaOH or $KOH,\$ phenol reacts with alkyl halide and gives phenolic ether ($C_{6}H_{5}OR$).
${C_{6}H}_{5}OH + NaOH\overset{\rightarrow}{- H_{2}O\ \ \ }C_{6}H_{5}O - Na\underset{- NaX}{\overset{\ \ \ \ \ \ RX\ \ \ \ \ \ }{\rightarrow}}C_{6}H_{5} - O - R$
Vapours of $C_{6}H_{5}OH\$ and $CH_{3}OH$, with red hot Th$O_{2}$(thoria) give anisole (phenolic ether).
$C_{6}H_{5}OH + CH_{3}OH\underset{\mathrm{\Delta}}{\overset{{\ \ \ ThO}_{2}\ \ \ }{\rightarrow}}C_{6}H_{5}OCH_{3} + H_{2}O$
anisole