To determine the possible molecular formula of the unknown compound, we need to analyze the mass spectrum data provided. The molecular ion peak at m/z 150 represents the molecular weight of the compound. The base peak at m/z 135 and the smaller peaks at m/z 91, 77, and 65 represent fragment ions formed by the loss of certain functional groups or atoms from the molecular ion.1. First, let's determine the molecular formula for the compound with a molecular weight of 150. We can use the nitrogen rule to check if the compound contains an odd or even number of nitrogen atoms. The nitrogen rule states that if the molecular ion peak has an even m/z value, the compound has an even number of nitrogen atoms 0, 2, 4, etc. , and if the molecular ion peak has an odd m/z value, the compound has an odd number of nitrogen atoms 1, 3, 5, etc. . In this case, the molecular ion peak is at m/z 150, which is even, so the compound has an even number of nitrogen atoms.2. Next, we can use the mass difference between the molecular ion peak and the base peak to identify possible functional groups or atoms that were lost during fragmentation. The difference between the molecular ion peak m/z 150 and the base peak m/z 135 is 15. This mass difference suggests the loss of a methyl group CH3 with a mass of 15.3. Now, we can subtract the mass of the methyl group from the molecular weight of the compound to get the molecular weight of the remaining fragment: 150 - 15 = 135.4. Based on the molecular weight of 150 and the even number of nitrogen atoms, we can propose a possible molecular formula for the unknown compound. One possible molecular formula is C9H12O2, which has a molecular weight of 150 and no nitrogen atoms. This formula is consistent with the mass spectrum data provided.It is important to note that mass spectrometry alone may not be sufficient to definitively identify the unknown compound. Additional analytical techniques, such as infrared spectroscopy, nuclear magnetic resonance spectroscopy, or elemental analysis, may be necessary to confirm the structure and molecular formula of the compound.