$(1) H_3C - C = C⊝\,(2) H - C = C⊝ \,(3) $ ${H_3}C\,\, - \,\,\mathop C\limits^\Theta {H_2}$
$1. \,{H_3}C - \mathop O\limits^ + {H_2} \to CH_3^ + + {H_2}O$
$2.\,{(C{H_3})_3}C - \mathop O\limits^ + {H_2} \to {(C{H_3})_3}{C^ + } + {H_2}O$
$3.\,{(C{H_3})_2}CH - \mathop O\limits^ + {H_2} \to {(C{H_3})_2}C{H^ + } + {H_2}O$

