HardChemistryHigh School (11–12)Organic Compounds with Functional GroupsNumerical

The mass spectrum of butan-2-ol, CH₃CH(OH)CH₂CH₃, is recorded…

Try it on paper first. A hint, the key idea and the worked solution are here when you need them.

The mass spectrum of butan-2-ol, $\text{CH}_{3}\text{CH}(\text{OH})\text{CH}_{2}\text{CH}_{3}$ , is recorded. Use the nominal masses C = 12, H = 1 and O = 16. Find the $m/z$ of the molecular ion. Find the $m/z$ of the peak from loss of a water molecule. A common break is next to the oxygen. Find the $m/z$ of the peak from loss of an ethyl group, which leaves the ion $\text{CH}_3\text{CH=OH}^+$ .

Need a reminder? The key ideaShow

Degree of unsaturation $= \dfrac{2C + 2 - H}{2}$ . Each group of equivalent hydrogens gives one NMR signal. The OH signal disappears with $\text{D}_2\text{O}$ . The molecular ion has $m/z = M$ . Zeisel: one AgI for each OCH $_3$ group, $w(\text{OCH}_3) = \dfrac{n(\text{AgI}) \times 31.034}{m(\text{sample})}$ .

The worked solution

Have you tried it?

Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.

← All Problems

← Count the signals in the proton NMR spectrum of each compound, counting each set of equivalent…Give the IUPAC name of each compound. CH₃CH₂CH₂CHO; CH₃CH₂COCH₂CH₃; (CH₃)₂CHCOCH₃… →

More onOrganic Compounds with Functional Groups

Discussion (0)

Loading…