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The molecular world
The molecular world

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5.2 Summary of Section 5

  1. The structural formulae of organic molecules can be divided into the carbon-hydrogen framework or skeleton, and the functional group(s). In the first approximation, the functional groups are the sites where reaction occurs, the framework remaining unreactive.

  2. This approximation works best when the framework consists of saturated carbon atoms.

Question 16

The compound ethene glycol (ethane-1,2-diol), HO—CH2—CH2−OH, is used as antifreeze in car engine coolants. Identify any functional groups in this molecule. Explain how you might make a powerful explosive from ethene glycol, and write down its structural formula.


The ethene glycol molecule contains two alcohol functional groups, —OH. These should both be replaceable by ONO2 groups when ethene glycol is treated with a mixture of concentrated nitric and sulfuric acids. The expected product has the structural formula Q.26. These expectations are correct. The product is a colourless liquid, ethene glycol dinitrate (EGDN), and it is indeed a powerful explosive.