Which alkene reacts fastest with Hbr ?
A) ch2=c(ch3)2
B) ch2=c(ch3)(och3)
C) ch2=c(ch3)(ch2och3)
Please choose the answer and explain y ? :)

Question

Which alkene reacts fastest with Hbr ? 
A) ch2=c(ch3)2
B) ch2=c(ch3)(och3)
C) ch2=c(ch3)(ch2och3)
Please choose the answer and explain y ? :)

aaronq · Answer

In an electrophilic addition of HBr to an alkene, the rate is determined by the stability of the carbocation formed ($3^o>2^o>1^o$).

The reaction begins with the addition of $H^+$ to one of the carbons forming the double bond, so being the reaction with this step to all your species and compare them.