Alexander Williamson prepared diethyl by a simple method, now called as Williamson's ether synthesis . In this method, an alkyl halide is treated with sodium alkoxide prepared from sodium and alcohol.

This reaction is used in the synthesis of symmetrical and unsymmetrical ethers.
It may be noted taht for preparing unsymmetrical ethers, the halide used should preferably be primary because secondary and tertiary alkyl halides may form alkenes as major product due to elimination process.
`CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-Br+underset("Sodium ethoxide")(Na^(+)O^(-)-C_(2)H_(5))rarrunderset("2-methylpropene")(CH_(3)-overset(CH_(3))overset(|)(C)=CH_(2))+C_(2)H_(5)OH+NaBr`
Aryl ethers or phenolic ethers can be prepared by using sodium phenoxide and alkyl halides. However, aryl halides and sodium alkoxide cannot be used for preparing phenolic ethers because aryl halides are less reactive towards nucleophilic substitution reaction
Arrange the following halides in decreasing order of reactivity towards Williamson's ether synthesis `:`
`underset((u))(CH_(3)CH_(2)CH_(2)Cl)," "underset((v))(CH_(3)CH_(2)CH_(2)Br),`
`underset((w))((CH_(3))_(3)C-CH_(2)Br)," "underset((x))(H_(2)C=CH-CH_(2)Cl)`

Options

A. (x) gt(v) gt (u) gt (w)
B. (u) gt (v) gt(w) gt (x)
C. (w) gt (x) gt(v) gt (u)
D. (v) gt (w) gt (x) gt (u)

Answer

A