Cartain materials such as turpentine oil, unsaturated organic compound, phosophorus, metals such as `Zn`, and `Pb`, etc., can absorb `O_(2)` from air in the presence of `H_(2)O`, which is converted to absorb `O_(2)` from air in the presence of `H_(2)O`, which is converted to `H_(2)O_(2)`. This is called autoxidation. Intermolecular redox reactions are those in which one molecule is oxidised and the other is reduced. Intramolecular redox reactions are those in which oen atom of a molecule is oxidised and the other atom is reduced.
Which of the following reactions is`//`are intermolecular redox reaction `(s)`

Options

A. `5KI+KIO_(3)+6HClrarr3I_(2)+6KCl+3H_(2)O`
B. `Fe+N_(2)H_(4)rarrNH_(3)+Fe(OH)_(2)`
C. `NO_(3)^(ө)+H_(2)S+H_(2)O+H^(o+)rarrNH_(4)^(o+)+HSO_(4)^(ө)`
D. `CrO_(7)^(2-)+2overset(ө)OHrarr2CrO_(4)^(2-)+H_(2)O`s

Answer

A, B, C

Explanation

It is also an intermolecular redox reaction.
a. It is an intermolecular redox reaction.
`{:(,2I^(ө),rarr,I_(2)+2e^(-),("Oxidation")),(10e^(-)+,2IO_(3)^(ө),rarr,I_(2),("Reduction")):}`
b. It is also an intermolecular redox reaction.
`{:(,Fe,rarr,Fe^(2+)+2e^(-),("Oxidation")),(2e^(-)+,N_(2)H_(4),rarr,2NH_(3),("Reduction")),(,2x = -4,,2x = -6,):}`
c. It is also an intermolecular redox reaction.
`{:(8e^(-)+,NO_(3)^(ө),rarr,overset(o+)(NH_(4)),("Oxidation")),(,x=5,,x+4=+1,),(,,,x = -3,),(,S^(2-),rarr,HSO_(4)^(ө)+8e^(-),("Oxidation")),(,x = -2,,1+x-8 = -1,),(,,,x=6,):}` d. It is, since the oxidation state of `Cr` in both reactant and product is `+6`.