Which one of the following reactions will not | vedclass

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(D) The Williamson ether synthesis involves the reaction of an alkoxide ion with an alkyl halide. For the reaction to proceed via $S_N2$ mechanism to

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$iso-BuO^{\ominus} Na^{\oplus} + sec-BuBr \rightarrow$ Elimination product

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(D) The Williamson ether synthesis involves the reaction of an alkoxide ion with an alkyl halide. For the reaction to proceed via $S_N2$ mechanism to form an ether,the alkyl halide should ideally be primary. If the alkyl halide is secondary or tertiary,the strong base (alkoxide) will prefer to undergo an $E2$ elimination reaction rather than $S_N2$ substitution. In option $A$,${}^{t}BuO^{\ominus}$ is a bulky base and $EtBr$ is a primary halide,so $S_N2$ is possible,but often elimination competes. However,in option $D$,$iso-BuO^{\ominus}$ is a base reacting with $sec-BuBr$ (a secondary alkyl halide). Due to steric hindrance and the nature of the secondary halide,the $E2$ elimination reaction is highly favored over $S_N2$ substitution,leading to alkene formation as the major product instead of the desired ether.

Column-$I$	Column-$II$
$(A)$ $CH_3-O-CH_3$	$(1)$ $C_6H_5OH + CH_3I$
$(B)$ $(CH_3)_2CH-O-CH_3$	$(2)$ $(CH_3)_3C-I + CH_3OH$
$(C)$ $(CH_3)_3C-O-CH_3$	$(3)$ $C_6H_5I + CH_3OH$
$(D)$ $C_6H_5-O-CH_3$	$(4)$ $CH_3OH + CH_3I$
	$(5)$ $(CH_3)_2CHOH + CH_3I$
	$(6)$ $(CH_3)_2CH-I + CH_3OH$
	$(7)$ $(CH_3)_3COH + CH_3I$

Which one of the following reactions will not lead to the desired ether formation in major proportion? (iso-$Bu$ $\Rightarrow$ isobutyl,sec-$Bu$ $\Rightarrow$ sec-butyl,$nPr$ $\Rightarrow$ $n$-propyl,${}^{t}Bu$ $\Rightarrow$ tert-butyl,$Et$ $\Rightarrow$ ethyl)

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