Question

We used 85% phosphoric acid in this reaction. What other acids could have worked to achieve similar results? Explain your answer.

Answer 1

simple logic is after donate the proton the obtained conjugate base should not act as a nucleophile

lets take the exaple HBr after donating H+ to alkene

alkene will form carbo cation and counter ion is Br-

in this case this Br- act as a nucleophile so

conjugate acid should not act as nucleophile if they act as a nucleophile we will get the substituted product rather than elimination product

another well known reagent for dehydration is sulphiric acid

one more exaple is paratolune sulphonic acid