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The standard electrode potential E^{\ominus } and its temperature coefficient \left ( \frac{dE^{\ominus }}{dT} \right ) for a cell are 2 V and -5\times 10^{-4}\; \; VK^{-1}at 300K respectively. The cell reaction is 

Zn(s)+Cu^{2+}(aq)\rightarrow Zn^{2+}(aq)+Cu(s)

The standard reaction enthalpy (\Delta _{r}H^{\Theta }) at 300 K in kJ mol -1 is , [UseR=8JK^{-1}mol^{-1}\: and \: F=96,000C\: mol^{-1}]

  • Option 1)

    -412.8

  • Option 2)

    -384.0

  • Option 3)

    192.0

  • Option 4)

    206.4

Answers (1)

best_answer

 

Gibbs energy of the reaction -

\Delta_{r}G=-nFE_{cell}

- wherein

\Delta _{r}G = gibbs energy of the reaction

E_{cell}= emf of the cell

nF = amount of charge passed

As we have learned in gibbs energy

\Delta G= -nFEu\mu =-2\times 96500\times 2= -386KJ

\Delta s= nF\frac{DE}{DT}= 2\times 96500\times \left ( -5\times 10^{-4}J/C^{0} \right )

= -96.5J

at 298K T\Delta S= 298\times \left ( -96.55 \right )=-28.8KJ

\Delta TconsTP

\Delta G= \Delta H-T\Delta S

\Delta H= \Delta G+T\Delta S= -386-28.8=-412.8Kj

 

 

Standard Electrode Potential -

If concentration of each species taking part in the electrode reaction is unity and further the reaction is carried out at 298 K, then the potential of each electrode is said to be the standard electrode potential.

-

 

 

Standard Electrode Potential Value -

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Option 1)

-412.8

Option 2)

-384.0

Option 3)

192.0

Option 4)

206.4

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