4. Reactivity considerations suggest that an unknown compound, which has the mass spectrum shown in Fig. 2, is a vinyl halide. Combustion analysis gave the following results: Carbon, 38.89 %; Hydrogen, 3.63 %. In order to finish the combustion analysis properly, the operator needs to know which halide to test for. Which halide would you suggest? Postulate a molecular formula for this unknown compound. Explanation of the fragmentation pattern is not required! 100 80 60 40 20 % of base peak 40 00 80 (mn) 8.0 182/184 10.1 120 0160 m/e mu261/263/265 Fig.2 197/199 200 240 Mass Spectrum M+ 276/278/280 280000