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The infrared spectrum of the compound with the mass spectrum shown below lacks a

ID: 985439 • Letter: T

Question

The infrared spectrum of the compound with the mass spectrum shown below lacks any significant absorption above 3000 cm-1. There is a distinct peak near 2750 cm-1 and another strong peak near 1730 cm-1. molecular ion: M+ = 100.

The infrared spectrum of the compound with the mass spectrum shown below lacks any significant absorption above 3000 cm1. There is a distinct peak near 2750 cm and another strong peak near 1730 cm molecular ion: M-100. 20 60 m/z Reprinted courten ef the Naticnal Instituid of Standards and Tecknolegy, U.S. Department of Commeret. Net eepyrightable in tke nited States Which of the following structures is consistent with the data? 0

Explanation / Answer

Option A is the correct answer.
It is an straight chain aldehyde.
In the IR spectrum, the peak at 1730 corresponds to carbonyl group of non conjugated aldehyde. Hence, options B and D (containing keto groups) are ruled out. The mass spectrum is characteristic of unbranched aldehyde as we can see M-18 peak (loss of water), M-28 peak (loss of ethylene), M-43 peak (loss of CH2=CH-O) and M-44 peak (loss of CH_2=CH-OH)