Which of the following ethers will undergo electrophilic substitution reaction?

Give $IUPAC$ names of the following ethers:
$(i)$ $C_2H_5OCH_2CH(CH_3)_2$
$(ii)$ $CH_3OCH_2CH_2Cl$
$(iii)$ $O_2NC_6H_4OCH_3(p)$
$(iv)$ $CH_3CH_2CH_2OCH_3$
$(v)$ $1$-Ethoxy-$4,4$-dimethylcyclohexane
$(vi)$ Ethoxybenzene

In Williamson synthesis of mixed ether having a primary and a tertiary alkyl group,if a tertiary halide is used,then:

Identify the product obtained when methyl bromide $(CH_3Br)$ reacts with sodium tert-butoxide $((CH_3)_3CONa)$.

Identify the missing product in the following reaction: $C_6H_5ONa + CH_3CH_2Br \rightarrow (?)$

Which of the following substances resists the nucleophilic attack of $OH^{-}$ ions?