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Characteristics of Chemical Reaction

A solution co...

Question

A solution contains Fe2+, Fe3+ and I ions. This solution was treated with iodine at 35C. E for Fe3+/Fe2+ is +0.77 V and E for I2/2I = 0.536 V.The favorable redox reaction is:
(1) $I^{-}$ will be oxidized to $I_{2}$
(2) $F e^{2 +}$ will be reduced to $F e^{3 +}$
(3) $I_{2}$ will be reduced to $I^{-}$
(4) there will be no redox reaction takes place
Please explain

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Solution

The explanation for the correct option
Option(1) $I^{-}$ is oxidized to $I_{2}$
The favorable redox reaction is one in which $E_{c e l l}^{0}$ is positive
It is given that for Fe, $E_{\frac{F e^{3 +}}{F e^{2 +}}}^{0} = 0.77 V a n d E_{\frac{F e^{2 +}}{F e^{3 +}}}^{0} = - 0.77 V$ it is the reduction potential of cathode
It is given that for iron, $E_{\frac{I_{2}}{2 I^{-}}}^{0} = 0.536 V a n d E_{\frac{2 I^{-}}{I_{2}}}^{0} = - 0.536 V$ it is the oxidation potential of anode
$E_{c e l l}^{0} = E_{c a t h o d e}^{0} - E_{a n o d e}^{0}$
$= (0.77 - 0.536) V$
$= 0.234 V$
The possible redox reaction is:
$F e^{3 +} + 2 I^{-} ⟶ I_{2} + F e^{2 +}$
That is $I^{-}$ is oxidized to $I_{2}$ and $F e^{3 +}$ is reduced to $F e^{2 +}$
Hence, Option(1) $I^{-}$ is oxidized to $I_{2}$ is correct

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Similar questions

Q. A solution contains

{F e}^{2 +}, {F e}^{3 +}

I^{-}

ions. This solution was treated with iodine at

35^{o} C

E^{0}

{F e}^{3 +} / {F e}^{2 +}

+ 0.77 V

E^{o}

I_{2} / 2 I^{-} = 0.536 V

. The favourable redox reaction is:

E_{F e^{2 +} / F e}^{\circ} = - 0.44 V and E_{F e^{3 +} / F e^{2 +}}^{\circ} = 0.77 V

E_{F e^{3 +} / F e}^{\circ}

E_{F e^{2 +} | F e}^{⊖}

E_{F e^{3 +} | F e^{2 +}}^{⊖}

are -0.44 and 0.77 V respectively.
If

F e^{2 +}, F e^{3 +}

F e

blocks are kept together, then:

Q. For the reaction,

F e^{3 +} + 3 e ⇌ F e, E^{o}

is -0.036 V and the standard electrode potential(SEP) for

F e^{3 +} + e ⇌ F e^{2 +}

is 0.77 V.
Hence,

E^{o}

F e^{2 +} + 2 e ⇌ F e

If $F e^{3 +} + y^{4 -} ⇌ F e Y^{⊖}; K_{f} = 1.3 \times 10^{25}$

$F e^{3 +} + Y^{4 -} ⇌ F e Y^{2 -}; K_{f} = 2.1 \times 10^{14}$

And $F e^{3 +} + e^{-} ⇌ F e^{2 +}; E^{⊖} = + 0.77 V$

E^{⊖}

F e Y^{⊖} + e^{-} \to F e Y^{2 -}

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