Question

How does Ozone react with the following?
(i) $PbS$ (ii) $C_2{H}_4$

(iii) $Ag$ (iv) $Hg$

Answer 1

Reaction of ozone $\left(O_3\right)$ with-

• (a) $PbS$- Ozone oxidises lead sulphide to lead sulphate. The reaction proceeds at room temperature.
  

$PbS+4O_3⟶\underset{\text{Lead sulphate}}{PbS{O}_4}+4O_2$

• (b) $C_2{H}_4$- The ozone molecule cleaves the $C=C$ double bond and gives formaldehyde and oxygen gas.
  

$C_2{H}_4+2O_3⟶\underset{\text{Formaldehyde}}{2HCHO}+2O_2$

• (c) $Ag$- Silver metal when warmed with ozone gets blackened due to reduction of the oxide formed in the initial stages of the reaction.

$2Ag+O_3\underset{-O_2}{\overset{}{\to }}\underset{\text{Silver oxide}}{{Ag}_{2}O}\stackrel{O_3}{\to }2Ag+2O_2$

• (d) $Hg$- When ozone is passed through mercury, it loses its meniscus and sticks to the glass due to the formation of mercurous oxide. This is called tailing of mercury. The meniscus can be restored by shaking it with water.
  

$2Hg+O_3⟶\underset{\text{Mercurous oxide}}{{Hg}_{2}O}+O_2$