In the given pair of compound, in which pair the second compoundis more reactive than first toward `S_(N^2)` reaction

Options

A. `CH_(3)-CH_(2)-Cl+CH_(3)-CH_(2)-O^(-)rarrEt-O-E" (or) "`
`CH_(2)-CH_(2)-Cl+CH_(3)-CH_(2)-OHrarrEt-O-Et`
B. `CH_(3)-CH_(2)-Cl+ErO^(-)rarrEt-O-Et" (or) "`
`CH_(3)-CH_(2)-Cl+ErS^(-)rarrCH_(3)-CH_(2)-S-Et`
C. `underset((1m))(Et)-Cl+underset((2m))(CH_(3))O^(-)rarrEt-O-CH_(3)" (or) "
`underset((2m))(Et)-Cl+underset((1m))(CH_(3))O^(-)rarrEt-O-CH_(3)`
D. `Et-Br+Ph_(3)PrarrEt-overset(oplus)PPh_(3)" (or) "`"
`Et-Br+Ph_(3)NrarrE+ -overset(oplus)NPh_(3)`

Answer

B

Explanation

`Ets^(Theta)` is more nucleophilic than `EtO^(Theta)`
(a) `CH_(3)-CH_(2)- O^(-) gt CH_(3)-CH_(2)-OH` charged `Nu^(-)` better than neutral.

More stable T.S. because ofmore bonding due to large size.
(c) Rate of `S_(N^2) alpha` [Substrate] `[Nu^(-)]`
It is equal for both 1 and 2.
(d) `Ph_(3) P gt Ph_3N`
`Et - overset(oplus) gt Et - overset(oplus) N Ph_3` more stable because more charge dispersion on larger atom.