Question

(CH3)3C-Br on reaction with NaOCH3 gives alkene instead of an ether

Answer 1

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Answer 2

The reaction you gave is an example of Williamson Ether Synthesis, which is a substitution reaction of SN2 type. It involves attack of alkoxide ion on the alkyl halide. In case of tertiary alkyl halide, product formed is unstable due steric reasons, therefore the product dehydrates to form an alkene.