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037. In 13C NMR, peak splitting is caused by which spin-spin interaction? a carb

ID: 547054 • Letter: 0

Question

037. In 13C NMR, peak splitting is caused by which spin-spin interaction? a carbon nucleus with the surrounding electrons b) carbon nucleolus with surrounding proton nuclei c) carbon nucleus and surrounding carbon nuclei d) carbon nucleus and electrons on adjacent nuclei Q38. Which of the following will NOT give a strong peak around 1700 wavenumbers? a) b) c) d) Q39. An aromatic ring usually has a 'HNMR spectrum containing a) peaks around 7 ppm b) a very broad ill-defined peak c) peaks around 1-2 ppm d) a single peak from all ronatic proton signals 040. In a proton NMR spectrum, a "doublet of triplets" indicates a) adjacent non-identical methyl groups b) two protons on a terminal alcohol c) the compound contains a labile proton d) a bi-substituted aromatic ring

Explanation / Answer

Q37

Answer: b) Carbon nucleolus with surrounding proton nuclei

The heteronuclear coupling (carbon-hydrogen) is common in carbon NMR as the probability of finding the two 13C atoms adjecent to each other in a molecule is very less.

Q38

Answer: a)

all the other options have carbonyl group (aldhyde & ketone) whose streching freqency will be around 1700 in the IR spectroscopy

alkene C=C or the aromatic C=C will appear in the range of 1450-1650

Q39

Answer: a) Peaks around 7 ppm

aromatic protons are deshielded due to Magnetic Anisotropy and appear around 7 in the 1H NMR spectrum

Q40

Answer: a) a bi-substituted aromatic ring

The OH group does not give the splitting.

The labile protons are fast exchanged and also does not give splitting.

methyl groups will give qurtet