Some chemical reactions of organic compounds
3 marks · NormalAn unknown organic reaction is described as: "A bromine molecule is added to an alkene, producing a dibromo compound." Explain, using ideas about reaction types, how you can deduce what type of reaction this is. Refer to the reactants and products in your explanation.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
It is an addition reaction because the reactants combine to form a single product and nothing is removed from the original molecule; bromine is added across the double bond of the alkene.
Must show: Reference to two reactants forming one product, Mention of atoms being added across a double bond, No atoms/groups are replaced/removed
Also accept: It is an addition reaction as two molecules combine to form one, with no atoms substituted or lost.
Common mistakes: Saying it is substitution; not mentioning both reactants or final product.
Show mark scheme and worked solution
Marking points
M1 · 1 mark · States that in the reaction, two reactants make a single product.
M1 · 1 mark · Explains that bromine is added across the double bond of the alkene.
A1 · 1 mark · Correctly concludes that this is an addition reaction, with clear reasoning.
Worked solution
Two reactants (alkene and bromine) react to produce one product, with no atom/group removed; bromine atoms are added across the double bond. Since nothing is substituted and atoms are added, this is an addition reaction.