Question

The mass spectrum of compound A shows the molecular ion at m/z 85, an M +1 peak at m/z 86 of approximately 6% abundance relative to M, and an M+2 peak at m/z 87 of less than 0.1% abundance relative to M. Assuming that compound A has only C, H, and one N atoms, determine the molecular formula, and then draw a possible structure if compound A has IR absorption at 1620-1680 cm^-1 but not at 3010-3090 cm^-1 .

Answer 1

(1). CH3-CH=N-CH2-CH2-CH3.

(2). CH3-CH2-CH =N-CH2-CH3.

(3). CH3-CH2-CH2-CH=N-CH3.

(3). CH3-CH2-CH2-CH2-CH=N.

Step-by-step explanation:

This is a spectroscopy question. Spectroscopy is an important part of chemistry which is used in the identification of chemical compounds.

So, without mincing words let's dive straight into the solution to the question.

Starting from values of IR given, the absorption at 1620-1680 cm^-1 shows the presence of C = N.

From the question, it is given that there is no signal showing on the spectrum at 3010 - 3090 cm^-1. The absorption at 3010 - 3090 cm^-1 shows the presence of N - H. But, it is not show on the spectrum. Hence, there is no N - H in the compound. That's, there are no Hydrogen atoms attached to Nitrogen atom.

We are given that the mass spectrum of compound A shows the molecular ion at m/z 85, therefore the molar mass of the compound is 85.

Also, from the question the elements present are carbon, Hydrogen and Nitrogen. Therefore, the compound is likely to be C5H11N.

The likely compounds are given below;

(1). CH3-CH=N-CH2-CH2-CH3.

(2). CH3-CH2-CH =N-CH2-CH3.

(3). CH3-CH2-CH2-CH=N-CH3.

(3). CH3-CH2-CH2-CH2-CH=N.