Given this IR, NMR, and MS, what is my unknown molecule?
MS spectra - Two isotopic molar ion peak are of same abundance so it means Br atom is there. Next abundant peak is at 91 which is 170-91 = 80
This also confirms Br is present.
H-1 NMR - Confirmed aromatic ring
IR also confirms - Aromatic ring
If we subtract mass of C6H4 and Br from 170 we are left with(15) a methyl group.
Methyl on aromatic ring is confirmed by H-NMR also (signals in the range of 7ppm to 8ppm.
Two H are more shielded and two are more deshielded and all 4 Hs are different.So it means aromatic ring is either ortho or meta.
Signals of H1 NMR are indicates multiple signals due to multiple splitting.
It means it can not be para so only two options are left - O-Bromotoluene or p-Bromotoluene. Analyze splitting in between 7 to 8 to identify it.