Sage-Tips

What happens when propene reacts with HBr in presence of hydrogen peroxide?

Reaction of HBr with propene in the presence of peroxide gives n-propyl bromide.

What is the function of hydrogen peroxide in the addition of HBr to an alkene?

Hint: When hydrogen bromide is added to alkenes in presence of peroxide, it reacts with anti-Markovnikov’s addition mechanism. Peroxides form free radicals that initiate the reaction and add bromine radical at terminal carbon.

What happens when propane is treated with HBr in presence of peroxide?

Markovnikov’s Rule is obeyed. In the presence of a peroxide such as HOOH, HBr adds to propene in an anti-Markovnikov sense and via a radical mechanism, giving 1-bromopropane.

Does the hydrogen peroxide oxidize or reduce the HBr?

Hydrogen bromide can be oxidized to bromine more effectively using hydrogen peroxide as the oxidant if a strong acid (e.g., sulfuric or phosphoric acid) is also present to increase the percent conversion of bromide to bromine.

Which of the following react with HBr in presence of a peroxide to give anti markovnikov product?

When $HBr$ reacts with propene in the presence of peroxide as catalyst it results in the formation of $n-$ propyl bromide. This is an anti-markovnikov addition reaction. When these free radicals react with hydrogen bromide, it extracts hydrogen from hydrogen bromide and gives bromine radical.

Which of the following alkenes reacts with HBr in the presence of a peroxide to give anti markovnikov’s product?

An alkene C6H12reacts with HBr in the absence as well as in the presence of peroxide to give the same product.

What is peroxide effect Why only hydrogen bromide shows this effect and not any other hydrogen halide?

HCl is a very stable acid H-Cl bond (430 kJ moH) is stronger than H-Br bond (378 kJ mol-1) and is not broken symmetrically by the free radicals generated by peroxide. Hence the free radical addition of HCl to alkenes is not possible.

Why does the peroxide initiated addition of HBr to alkenes result in the anti-Markovnikov addition of HBr?

The reason that hydrogen bromide adds in an anti-Markovnikov fashion in the presence of organic peroxides is simply a question of reaction rates. With the other hydrogen halides, the opposite is true. Hydrogen fluoride. The hydrogen-fluorine bond is so strong that fluorine radicals aren’t formed in the initiation step.

Which of the following react with HBr in presence of peroxide to give anti markovnikov product?

(A) Addition of HBr ot alkene in presence of peroxide gives anti-Markownikoff product. (R) This addition follows ionic mechanism .

What would be the main product when propane reacts with HBr in presence of benzoyl peroxide?

Propene reacts with HBr in presence of benzoyl peroxide to give 1-bromopropane. In presence of peroxide , the addition of HBr to propane occurs by free radical mechanism.

Which of the following alkenes will react with HBr in presence of peroxide to give anti-Markovnikov product?

How does HBR react with organic peroxides?

Hydrogen Halides like HBr usually react with alkenes using an electrophilic addition mechanism. However, in the presence of organic peroxides, HBr adds to the carbon across the double bond which carries a lesser number of hydrogen atoms. This is called Anti-Markownikoff’s rule. This is called peroxide effect or Anti-Markovnikovs rule.

Why does hydrogen bromide not follow Markovnikov’s rule?

Because the HBr adds on the “wrong way around ” in the presence of organic peroxides, this is often known as the peroxide effect or anti-Markovnikov addition. In the absence of peroxides, hydrogen bromide adds to propene via an electrophilic addition mechanism. That gives the product predicted by Markovnikov’s Rule.

Why does HBR add to propene the wrong way around?

Because the HBr adds on the “wrong way around ” in the presence of organic peroxides, this is often known as the peroxide effect or anti-Markovnikov addition. In the absence of peroxides, hydrogen bromide adds to propene via an electrophilic addition mechanism.

Can halo acids replace HBr in anti Markovnikov reaction?

Interestingly, other halo acids (HF, HCl, HI) cannot replace HBr in the anti-Markovnikov reaction (i.e., in the presence of H2O2). This reaction only works with HBr. In the absence of free radicals, halide acids like hydrochloric add to alkenes by an ionic process.