How does HBr add across a double bond? Predict the regiochemistry when HBr is reacted with 2-methylpropene

When HBr is dissolved in solution it dissociates in its two major components: H+ and Br-. The acidic environment promotes nucleophilic of the alkenes to the electrophilic protons to form an intermediate carbocation. The carbocation is the subsequently quenched by nucleophilic attack of the bormide ion to give the desired product. When predicating the regiochemistry for the addition of HBr into alkenes, the H+ will added to the carbon atom that generates the most sable carbocation – Markovnikov’s rule. Therefore the addition of HBr to 2-methylpropene would give 2-bromo-2-methylpropane.

RM

Related Chemistry A Level answers

All answers ▸

An alcohol, X has an Mr of 74 and percentage composition of 64.9% Carbon, 13.5% Hydrogen and 21.6% Oxygen. It does not turn potassium dichromate (VI) green. Determine the structural formula of X, and state its name.


State the trend in electronegativity for the elements of group 17 and explain why this trend occurs.


How do you determine the shape and bond angle of an ammonia molecule?


Explain, in general, how a catalyst works