Practice Problem: Assigning Molecular Structure From an NMR Spectrum

The video tutorial explains how to analyze NMR spectra to determine the structure of a compound with the empirical formula C4H9BR. It covers methods for identifying structural isomers, assigning peaks using integration, splitting, and chemical shift data, and provides a detailed analysis of proton peaks. The tutorial emphasizes the importance of understanding the chemical environment and using empirical data to deduce the correct structure.

What is the empirical formula of the compound discussed in the NMR spectroscopy problem?

• C4H9BR

• C3H7BR

• C4H8BR

• C5H10BR

How many structural isomers are possible for the empirical formula C4H9BR?

• Five

• Four

• Three

• Two

What is a common feature of chemically equivalent protons in NMR spectroscopy?

• They produce peaks at random locations

• They do not produce any peak

• They produce the same peak

• They produce different peaks

What does a peak that integrates to six in an NMR spectrum often indicate?

• A CH2 group

• Two identical methyl groups

• A CH3 group

• A single methyl group

What does the N + 1 rule help determine in NMR spectroscopy?

• Molecular weight

• Chemical shift

• Splitting pattern

• Integration

Which peak is expected to be the furthest upfield in the NMR spectrum?

• Peak D

• Peak C

• Peak B

• Peak A

What is the splitting pattern called when there are more than five neighboring protons?

• Singlet

• Multiplet

• Triplet

• Doublet