Weak sulfuric acid attack, example

Bromide, the nucleophile, is not involved in the rale-determining step, so we know that the rate of the reaction will be independent of the concentration of Br". But what happens if wc use an acid whose counterion is such a weak nucleophile that it doesn t even attack the carbon of the carhoca-tion Here is an example—f-butanol in sulfuric acid doesn t undergo substitution, but undergoes elimination instead. 

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