A certain hydrocarbon1 with molecular formula C6H12 undergoes bromination with Br2 and light to produce only one monobromo compound 2, upon treatment of 2 with sodium ethoxide as well as ethanol compound 3 is obtained which can be converted to 1 by treatment with H2/Pt. Compound three reacts with ozone followed by Zn.H2O to produce only one compound 4 (C6H10O2). Suggest structures for 1, 2, 3 and 4 that account for these facts.