Hydrocarbons - Addition Reactions

The reaction where bromine (Br2) is added to an alkene to test for unsaturation. The reddish orange color of bromine solution disappears in the presence of an alkene.

A chemical reaction where a molecule adds to an alkene, breaking the double bond and forming a single bond.

A rule that predicts the regioselectivity of electrophilic addition reactions to alkenes. It states that the negative part of the adding molecule will attach to the carbon atom with fewer hydrogen atoms.

A cyclic intermediate formed during the electrophilic addition of halogens to alkenes. It consists of a halogen atom bonded to two carbon atoms of the alkene.

A type of chemical reaction where an alkene reacts with a hydrogen halide (HCl, HBr, HI) to form an alkyl halide.

A compound containing only carbon and hydrogen atoms.

A type of hydrocarbon containing at least one carbon-carbon double bond.

Addition of HBr to an unsymmetrical alkene in the presence of peroxide, forming a product contrary to Markovnikov's rule. This reaction is specific to HBr and occurs due to the formation of a more stable free radical intermediate.

A reaction mechanism where a free radical acts as an intermediate, leading to the formation of a new product. In the case of anti-Markovnikov addition, the peroxide initiates the formation of a bromine radical.

A species with an unpaired electron, highly reactive and capable of initiating chain reactions. In anti-Markovnikov addition, a bromine radical is formed.

The tendency of a free radical to add to the carbon atom with the larger number of hydrogen atoms, forming a more stable free radical intermediate.

The strength of a bond determines its susceptibility to breaking by free radicals. In anti-Markovnikov addition, HBr bond is weaker than HCl, making it more likely to be cleaved by a radical.

The phenomenon observed in anti-Markovnikov addition where only HBr reacts with peroxide, while HCl and HI do not. This is due to the relative bond strengths of H-X bonds.

An intermediate formed in the anti-Markovnikov addition reaction. It is a cyclic molecule with a halogen atom bonded to two carbon atoms.

The formation of a bond between an atom or molecule and a double bond, breaking the double bond and forming two single bonds. In anti-Markovnikov addition, HBr reacts with the alkene double bond.

An organic compound containing only carbon and hydrogen atoms. Alkenes are a type of hydrocarbon with at least one carbon-carbon double bond.

A reaction where a molecule adds to an alkene, breaking the double bond and forming a single bond.

A reaction mechanism that proceeds through a series of steps involving free radicals. This mechanism is often observed in the addition of HBr to alkenes in the presence of peroxides.

When a covalent bond breaks, with each atom taking one electron, forming two free radicals.

A covalent bond breaking where both electrons go to one atom, forming a negative ion and a positive ion.

The systematic naming of organic compounds according to the rules established by the International Union of Pure and Applied Chemistry.

Hydrogen halides (HI, HBr, HCl) react with alkenes in an electrophilic addition reaction, where the hydrogen atom of the hydrogen halide attaches to one carbon atom of the double bond and the halogen atom attaches to the other carbon atom.

The addition of hydrogen halides to symmetrical alkenes (those with similar groups attached to the double bond) forms only one product.

A carbocation is a positively charged species where a carbon atom has only three bonds and carries a positive charge.

The stability of a carbocation increases with the number of alkyl groups attached to the positively charged carbon atom. Tertiary carbocations are the most stable.

During the addition of HBr to an unsymmetrical alkene, a carbocation intermediate is formed. The carbocation is then attacked by the bromide ion, leading to the formation of the product.

The more stable carbocation intermediate is formed faster, as it is energetically more favorable. This determines which product is formed in a higher yield.

The order of reactivity of hydrogen halides in electrophilic addition reactions is HI > HBr > HCl. This is because the strength of the H-X bond decreases down the group, making HI the most reactive and HCl the least reactive.

A reaction where alkenes react with cold, dilute, aqueous potassium permanganate (KMnO4) to form vicinal glycols (diols with hydroxyl groups on adjacent carbons). This reaction is often used as a test for unsaturation, as the purple color of KMnO4 disappears upon reaction with an alkene.

A type of chemical reaction where small molecules called monomers join together to form large molecules called polymers. This usually occurs at high temperatures, pressures, and in the presence of a catalyst.

The small, repeating units that make up a polymer chain.

A chemical reaction where an alkene is oxidized to form a ketone or carboxylic acid.