91Ó°ÊÓ

From the given NMR spectrum, it was observed that, the chemical shift value occurs at 4.0 which suggests presence of electronegative atom as electronegative atom increases the chemical shift value of an adjacent proton by making the electron density less available and making the environment around that proton deshielded. Further splitting pattern confirmed that the electronegative atom is oxygen and since broad singlet is observed at 2.5 chemical shift value, this indicates presence of hydroxyl group. Chemical shift value of 1.2 indicates presence of methyl group and from the splitting patterns it is confirmed that structure would be propan-2-ol.

Propan-2-ol

A give signal will split and that splitting arises from spin-spin coupling which means the interaction which takes place between neighboring and non-equivalent nuclei. A septet is observed for proton-a, as the proton-a is surrounded by two methyl groups which means 6 hydrogens will split the signal for this one proton into septet. A doublet pattern is observed for both methyl groups as there is only one proton which is present that is of methine carbon which can take part in splitting. A broad singlet is observed for hydroxyl proton, as hydroxyl proton is acidic and thus is rapidly exchangeable and there is no proton present nearby which split this hydroxyl proton, thus a singlet is observed.

b = δ 2.5 (broad singlet, 1H)

c = δ 1.2 (doublet, 6H)