The 1 H NMR spectra for methanol at room temperature and -40 0 C should be sketched. Concept introduction: Hydroxyl group in methanol involves in H bonding. But at high temperatures, these hydrogen bonding is weakened and its signal is shielded due to the increase in the rate of intermolecular proton exchange. So at room temperature the two types of H are undetectable in NMR. But at low temperatures, formation of H bonding is encouraged and lowers the rate of proton exchange. So, at low temperatures two types of H are detectable hence, spin-spin coupling can be observed.

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Chapter 19, Problem 19.19QAP

Interpretation Introduction

Interpretation:

The ¹H NMR spectra for methanol at room temperature and -40⁰C should be sketched.

Concept introduction:

Hydroxyl group in methanol involves in H bonding. But at high temperatures, these hydrogen bonding is weakened and its signal is shielded due to the increase in the rate of intermolecular proton exchange. So at room temperature the two types of H are undetectable in NMR. But at low temperatures, formation of H bonding is encouraged and lowers the rate of proton exchange. So, at low temperatures two types of H are detectable hence, spin-spin coupling can be observed.

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