Spectroscopic data for two carboxylic acid derivatives are given in NMR-A and NMR-B. Identify these compounds, which may contain C, H, O, N, Cl, and Br but no other elements. 

(a) ¹H NMR: spectrum A (one signal has been amplified to reveal all peaks in the multiplet). IR: 1728 cm^-1. High-resolution mass spectrum: m/z for the molecular ion is 116.0837. See table for important MS fragmentation peaks. 

(b) ¹H NMR: spectrum B. IR: 1739 cm^-1. Highresolution mass spectrum: The intact molecule gives two peaks with almost equal intensity: m/z = 179.9786 and 181.9766. See table for important MS fragmentation peaks. 

Transcribed Image Text:

Mass Spectrum of Unknown A Intensity relative to base peak (%) m/z 116 0.5 101 12 75 26 57 100 43 66 29 34