To determine the molecular formula of the unknown compound, we will first consider the M+ peak at m/z 86. This peak represents the molecular ion M+ of the compound, which is the intact molecule with a positive charge. The m/z value of the M+ peak corresponds to the molecular weight of the compound.Given the molecular weight of 86, we can now consider the possible elemental composition of the compound. Since it is an organic compound, it will most likely contain carbon, hydrogen, and possibly oxygen and/or nitrogen.We can start by calculating the maximum number of carbon atoms that could be present in the compound. The molecular weight of carbon is 12, so the maximum number of carbon atoms would be 86/12 7. However, we should also consider the presence of hydrogen, oxygen, and nitrogen atoms.The molecular weight of hydrogen is 1, oxygen is 16, and nitrogen is 14. We can now try different combinations of these elements to find a molecular formula that adds up to a molecular weight of 86.One possible molecular formula is C4H10O, which has a molecular weight of 4 x 12 + 10 x 1 + 1 x 16 = 48 + 10 + 16 = 74. This molecular formula does not match the given molecular weight of 86.Another possible molecular formula is C5H12, which has a molecular weight of 5 x 12 + 12 x 1 = 60 + 12 = 72. This molecular formula also does not match the given molecular weight of 86.A third possible molecular formula is C4H9N, which has a molecular weight of 4 x 12 + 9 x 1 + 1 x 14 = 48 + 9 + 14 = 71. This molecular formula does not match the given molecular weight of 86 either.Finally, we can try the molecular formula C6H14, which has a molecular weight of 6 x 12 + 14 x 1 = 72 + 14 = 86. This molecular formula matches the given molecular weight of 86.Therefore, the molecular formula of the unknown compound is C6H14.However, it is important to note that mass spectrometry alone may not be sufficient to definitively determine the molecular formula of an unknown compound. Additional analytical techniques, such as infrared spectroscopy, nuclear magnetic resonance spectroscopy, or elemental analysis, may be necessary to confirm the molecular formula and elucidate the compound's structure.