${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\underset{413\mathrm{K}}{\overset{\mathrm{Conc}. {\mathrm{H}}_2{\mathrm{SO}}_4}{\to }}\mathrm{A}\underset{∆}{\overset{\mathrm{Conc}.\mathrm{HI}(\mathrm{excess}}{\to }}\mathrm{B}\stackrel{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{ONa}}{\to }\mathrm{C}$
Formation of ‘A’ from C₂H₅OH and formation of ‘C’ from ‘B’ involve the same mechanism. The mechanism is