Sir in these structures positive charge appears on c2 and c4 but then also they have put positive charg. on whole carbon of resonance hybrid 1,

1, 3-Butadiene This intermediate carbocation is allylic in nature and hence can be regarded as a resonance hybrid of two equivalent structures ( and II) : CH4CHCH-CH,Br CH-CH = CH-CH,Br = CH,-CH-CH-CHBr 2 II 3 Resonance hybrid Step 2. Since in the resonance hybrid, the positive charge is almost equally distributed between caro atoms as indicated in 1 and lI, the attack of bromide ion can occur on either of these. If the attack occurs CL2-addition product results and if it occurs on C 1 Ladditi