Question

In which one of the following reactions does ozone act as a reducing agent?
A. $Ba{O_2} + {O_3} \to BaO + 2{O_2}$
B. $2HCl + {O_3} \to C{l_2} + {H_2}O + {O_2}$
C. $PbS + 4{O_3} \to PbS{O_4} + 4{O_2}$
D. $2KI + {O_3} + {H_2}O \to 2KOH + {I_2} + {O_2}$

Answer 1

Hint: For solving this question, first we need to understand the physical and chemical properties of ozone. We know that ozone is a dipolar molecule due to which it has characteristic properties. And it reacts selectively with substances. Thus, ozone is considered to be electrophilic.

Complete step by step answer:
First, we need to understand the meaning of a reducing agent. We can define a reducing agent as an element or a compound that loses an electron to an electron recipient in a redox chemical reaction. Thus, a reducing agent is oxidized when it loses electrons from the outermost shells in a redox reaction.
According to the question, we know that ozone gets reduced to peroxides and peroxides are reduced to oxides. Then, the oxides get reduced to form oxygen.
$
  {H_2}{O_2} + {O_3} \to {H_2}O + 2{O_2} \\
  Ba{O_2} + {O_3} \to BaO + 2{O_2} \\
 $
​Here, we can see that barium peroxide is reduced to Barium oxide.
So, from the above reaction we get to know oxidation state of Ba:
$+4$ To $ +2$
$Ba{O_2} + {O_3} \to BaO + 2{O_2}$
From the above reaction it is evident that the oxidation state of Ba changes from +4 to +2. Therefore, we can conclude that Ba is being reduced by ${O_3}$ ​. So, in this reaction, we get to know that ozone ${O_3}$ acts as a reducing agent.

So, the correct answer is Option A.

Note:
We need to note that ozone also serves as a strong oxidizing agent as an atom of nascent oxygen that is more reactive than oxygen and it will quickly decompose. So, we can say that a strong oxidizing agent absorbs and reduces electrons, and is usually described by halogens or an oxygen-consisting product.