В первой реакции скорее всего СH3Br.
1)Ch3-C2H4 - (CH2)2 - CH3Br + KOH = CH3-C2H4-CH2-CH=CH2+KBr+ H2O
2)CH3-C2H4-CH2-CH=CH2+H2O = CH3-C2H4-CH2-CHOH-CH3
3)CH3-C2H4-CH2-CHOH-CH3 = CH3-C2H4-CH=CH-CH3 +H2O
4)CH3-C2H4-CH=CH-CH3 +Br2 = CH3-C2H4-CHBr-CHBr-CH3
5)CH3-C2H4-CHBr-CHBr-CH3 + 2KOH = CH3-C2H4-CH-=(Тройная связь)CH-CH3 + 2KBr +2H2O
Вроде всё так....