Solving a problem in chemistry section 11 point 4

4. Two of unsaturated hydrocarbon having the general formula CnH2n - 2 belong to different classes of compounds, their density vapor neon is 3.4. Both substances decolorized bromine water, one of which forms a precipitate with an ammoniacal solution of silver oxide. Determine hydrocarbons, taking into account that they have a branched structure, and one of them is used for the production of synthetic rubber. Write the equations of all the reactions mentioned.