Question

Hydrogen peroxide oxidises [Fe(CN)₆]^4- to [Fe(CN)₆]^3- in acidic medium but reduces [Fe(CN)₆]^3- to [Fe(CN)₆]^4- in alkaline medium. The other products formed are, respectively.

• A. (H₂O+O₂) and (H₂O+OH^–)
• B. H₂O and (H₂O+O₂)
• C. H₂O and (H₂O+ OH^–)
• D. (H₂O+O₂) and H₂O

Answer 1

The correct option is B

H₂O and (H₂O+O₂)

Explanation for the correct option:

Oxidation of Hydrocarbon: All hydrocarbons react in the air to form carbon monoxide and then through a series of reactions to form carbon dioxide.

• The first step is always the reaction between a hydrocarbon and a hydroxyl radical.
• With alkanes, the hydroxyl radical abstracts a hydrogen atom and forms a carbon-centered radical.
• When Hydrogen peroxide oxidizes to ${[{\mathrm{Fe}}^{+3}{\left(\mathrm{CN}\right)}_6]}^{3-}$ in an acidic medium, the reaction takes place as:${[{\mathrm{Fe}}^{+2}{\left(\mathrm{CN}\right)}_6]}^{4^{-}}+{\mathrm{H}}_2{\mathrm{O}}_2+2{\mathrm{H}}^{+}\to {[{\mathrm{Fe}}^{+3}{\left(\mathrm{CN}\right)}_6]}^{3-}+2{\mathrm{H}}_2\mathrm{O}$
• From the above reaction, we see that hydrogen peroxide oxidizes to ${[{\mathrm{Fe}}^{+3}{\left(\mathrm{CN}\right)}_6]}^{3-}$ in an acidic medium the other product form is when Hydrogen peroxide reduces $[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6{]}^{3-}\text{to}[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6{]}^{4-}$ in an alkaline medium, the reaction is:${[{\mathrm{Fe}}^{+3}{\left(\mathrm{CN}\right)}^6]}^{3-}+{\mathrm{H}}_2{\mathrm{O}}_2+2{\mathrm{OH}}^{-}\to {[{\mathrm{Fe}}^{+2}{\left(\mathrm{CN}\right)}^6]}^{4-}+{\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}$
• From the above reaction, we see that Hydrogen peroxide oxidises $[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6{]}^{3-}\text{to}[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6{]}^{4-}$ in an alkaline medium, and the other product form is ${\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{O}}_2$.

(b) H₂O and (H₂O+O₂): We can see from the given equation in acidic and in the alkaline medium the other product formed is H₂O and (H₂O+O₂).

Explanation for the incorrect option:

(a) (H₂O+O₂) and (H₂O+OH^–): From the given reaction we can see in acidic and in alkaline medium only H₂O and (H₂O+O₂) is formed but there are no traces of OH^- formed.

(c) H₂O and (H₂O+ OH^–): From the given reaction we can see in acidic and in alkaline medium only H₂O and (H₂O+O₂) is formed but there are no traces of OH^- formed.

(d) (H₂O+O₂) and H₂O: From the given reaction (H₂O+O₂) and H₂O are formed but not in this order. First H₂O will form then H₂O+O₂ will form.

Hence, option (B) is the correct answer.