**Williamson's synthesis** of $(\text{CH}_3)_3\text{C-O-CH}_3$ would best use:
A$(\text{CH}_3)_3\text{C-Cl}$ + $\text{CH}_3\text{ONa}$
B$(\text{CH}_3)_3\text{C-ONa}$ + $\text{CH}_3\text{Cl}$
CTwo molecules of $(\text{CH}_3)_3\text{C-OH}$
DBoth A and B equally
Answer & Solution
Correct answer: B. $(\text{CH}_3)_3\text{C-ONa}$ + $\text{CH}_3\text{Cl}$
S$_N$2 needs less-hindered substrate. tert-butyl chloride would undergo elimination, not substitution (3° halide + strong base → alkene). Use bulkier alkoxide (t-BuO⁻) + smaller alkyl halide (CH₃Cl). Williamson rule: alkoxide from the bulkier side + alkyl halide from the smaller side.