Ethers can be prepared by Williamson synthesis which an alkyl halide is reacted with sodium alkoxide. Di-tert-butyl ether can't be prepared by this method. Explain.

Explanation

In order to prepare di-tert butyl ether, sodium tert-butoxide must be reacted with tert-butyl bromide. Alkoxides are not only nucleophiles but they are strong base as well. They react with `3^(@)` alkyl halides leading to the elimination reaction.
When tert-butyl-bromide reacts with sodium tert-butoxide instead of substitution, elimination takes place. As a result of this elimination reaction, Iso butylene is formed instead of di-tert butyl ether.
`{:(" "CH_(2)-H" "CH_(3)" "CH_(2)" "CH_(3)) ,(" |"" |"" ||"" |" ),(H_(3)C-C-Br+Na-O-C-CH_(3) overset("Elimination")rarr H_(3)C-C-CH_(3)+H_(3)C-C-OH+NaBr),(" |"" |" " Iso-butylene" " |" ),(" "CH_(3)" "CH_(3)" "CH_(3) ),("Tert-butyl bromide Sodium.tert butoxide 2-methylpropan-2-ol"):}`
`{:(" "CH_(2)-H" "CH_(3)) ,(" |"" |" ),(H_(3)C-C-Br+Na-O-C-CH_(3) overset("Substitution")rarr "No reaction"),(" |"" |" ),(" "CH_(3)" "CH_(3) ),("Tert-butyl bromide Sodium.tert butoxide"):}`