A technician has two colourless liquid hydrocarbon samples, J and K. A small amount of bromine water is added to each sample and the mixtures are shaken.
| Sample | Observation |
|---|---|
| J | The bromine water remains orange. |
| K | The bromine water changes from orange to colourless. |
The technician wants to use one of the samples to make a polymer.
Explain which sample contains molecules that can act as monomers in addition polymerisation.
Describe how the carbon-carbon bonds in molecules of the chosen sample change as the polymer chain forms.