Answer:
Addition reaction.
Explanation:
There are four possible type of reactions in an organic compound, generally.
a) substitution: where a group or atoms substitutes another group or atom. for example reaction of an alkyl halide with hydroxide ion to give alcohol, where hydroxide ion replaces a halide ion.
b) elimination: Where a group or atom get eliminated from a molecule. For example synthesis of an alkene from an alkyl halide by elimination of hydrogen and halogen.
c) rearrangement: Here there is no addition or substitution or elimination but the molecule undergoes some atomic rearrangements to give a stable form.
d) Addition : in this there is addition of a molecule on a double bond.
In the given example the alkene is undergoing addition reaction as hydrogen is being added on it to give saturated alkane molecule.
