Question

How do you prepare $K{O_3}?$ Mention the magnetic behaviour of $O_3^ -$ .

Answer 1

Potassium ozonide, $K{O_3}$ , is prepared by passing ozone over potassium hydroxide $(KOH)$ . Ozone acts as a good oxidising agent either by accepting electrons or by donating oxygen atoms. The magnetic behaviour of the product formed can be measured by counting the number of unpaired electrons in it.

Complete answer: Potassium hydroxide $(KOH)$ commonly known as caustic potash is a strong base gives potassium ozonide ,$K{O_3}$, on passing ozone over it. Ozone $({O_3})$ or trioxygen is an allotrope of ${O_2}$ .It is a good oxidising agent . An oxidising agent oxidises another molecule by either accepting electrons or by donating oxygen atoms and reduces itself. While a reducing agent reduces another molecule and gets oxidised by itself. The balanced chemical equation of the formation of potassium ozonide from dry potassium hydroxide and ozone is:
$2KOH\,\, + \,\,5{O_3}\,\, \to \,\,2K{O_3}\,\, + \,\,5{O_2}\,\, + {H_2}O$
The reaction takes place at low temperature and a deep red coloured solid ( $K{O_3}$) is formed along with the liberation of oxygen gas.
A paramagnetic molecule contains an unpaired electron in it while a diamagnetic molecule does not contain any unpaired electron. Paramagnetic molecules get weakly attracted by magnets but diamagnetic molecules do not. Ozonide ion, $O_3^ -$ , has an odd number of electrons and is paramagnetic. It contains unpaired p-electrons due to which it exhibits colour.

Note:
$K{O_3}$ is an inorganic ozonide. Such ozonides can be prepared by either burning potassium or heavier alkali metals in the presence of ozone or by passing ozone over alkali metal hydroxides. Ozonides of Li and Na are unstable because the size of ozonide anion is very large compared to the size of these alkali metal cations.