Determining identity of unknown compound with NMR data I have the following IR spec, C NMR and H NMR data. The boiling points determined for the unknown compound were 116.8 and 119.1°C (two trials). Given the possible compounds, the unknown can be one of: 
3-methyl-2-butanol
1-butanol
3-pentanol
2-pentanol
2-methyl-1-butanol. (These are based on boiling point)
I have eliminated some of these choices based on the number of different types of carbons (4, as shown on C NMR) but am not sure where the H of the OH is indicated in H NMR. There is no singlet present among the 3 groups of peaks, so where would it be?
Peaks of acidic protons in an NMR spectrum can change (in position, form and intensity) due to exchange with other volatile protons.


A very fast exchange makes the peaks coalesce, you get one singlet between the two "original" (expected) chemical shifts, the exact position depends on the respective amount of both. 
A slower exchange, one "on the NMR timescale", broadens that peak considerably, typical case is residual water and a COH proton. The peak might in some cases be so broad it becomes invisible.
Even slower, this peak splits into two, which become sharper and further removed from each other.
A very slow exchange makes no change to the positions, but an exchange with deuterium (i.e. from the solvent) changes the relative intensity of the respective peaks over time.