Question

Complete the following reactions

(i) CH2=CH2 + H2

→

523−573

(ii) CH3-CH=CH2 + HBr​

Answer 1

The complete question is:

complete the following reaction:

(1) CH2= CH2 + H2  pt/523 - 573k →

(2) CH3 - CH = CH2 + HBR →

• This reaction is known as hydrogenation of ethene. The complete reaction is as follows:

CH₂=CH₂ + H₂ pt/523-573 K → CH₃-CH₃

• When propene reacts with HBr it gives 2- bromopropane (major product) and 1- bromopropane (minor product). We get two products due to the s=unsymmetrical nature of propene. The addition of bromine is done on the basis of Markonikov rule. The complete reaction is as follows:

CH₃-CH=CH₂ + HBR → CH₃CH₂CH₂Br + CH₃CH₂BrCH₃

Answer 2

Complete the following reactions

(i) CH2=CH2 + H2 :

This is an example of Addition reactions :The reaction in which an unsaturated hydrocarbon combines with hydrogen to give a saturated hydrocarbon in presence of a catalyst like Ni[NICKEL]

                                    Ni

Ethene + Hydrogen --------------> Ethane

                                  heat

                           Ni

CH2=CH2 +H2 -------->CH3-CH3

                          HEAT

II) CH3-CH=CH2 + HBr​ :

This is an example of Addition reaction. he double bond is broken and hydrogen and bromine are added to the given compound.  

Bromine will add up on secondary carbon. (Markovnikov's Rule)

CH3 -CH=CH2+HBR ---->CH3 CH(Br)−CH3

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