the particles' energy becomes greater than the potential barrier of the interaction field with the other particles.
i think the answer is the second one
the given alcohol is octanol. it is a primary alcohol and will easily get oxidized in presence of strong oxidizing agent potassium dichromate.
the reaction is shown in the diagram below. the carbon bearing hydroxyl group will oxidized.
octanol will be oxidized completely to octanoic acid. it it would be tertiary alcohol which is hard to oxidized easily.
o2 yields 2o2-