Shweta thakur Asked a Question
March 27, 2021 9:50 pmpts 30 pts
Example 2. The EMF of the ell Ca,CáCl%.2-5H,O(saturated) |1 AgCl), Ag in wbich the cel ection s Ca)+ 2AgCK) + aq CaCl:5/2 H,0 (sat.) + 2Ag) is 0-6753 V at 25°C and -6915 V at O°C. Calculate the free energy change (AG), enthalpy change (A) and entropy change (A5) of tbe cell reaction at 25°C. Solution : 1. Free Energy Change (a6); : The cell reaction, requires 2 faradays of electriciy for its completiom since n=2 Free energy change is given by the relation -AG nFE (= V C) AG-2 mol x 96,485 C mol" x0-6753 VV =- 130,3329J = - 130-33 kJ Enthalpy Cbange (AF) : The EMF of the cell is given by (Eq. 4) In this case, EMF decreases with increase in temperature, i.e., (©ElGIp is negative. Thus, --6915 V-0-6753V 25 K 0-00065 V K at atmospheric pressure 0-6753 2molx96,485 C mol mol-T+ 298 K (-0-00065 V K-) aH 16717 joules=- 167-72 kJ 3. Entropy Change (A5) The eatropy change is related to enthalpy change and free energy change by the well known thermodynamc expression, AG = AH -7AS. -AS AG-AH . -130-331 lo-232 - 01238 K 128J K 298 K
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  • Achyut ranjan gogoi
    this relationship is thermodynamic behaviour with emf.
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  • Achyut ranjan gogoi Best Answer
    see according to nernst equation we can tell that if the temperature is increase emf decreases but in this question it has given ∆e/∆t that means how emf is variate with temperatur...
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    Shweta thakur
    thanku so much sir
  • Suman Kumar thankyou
    it is given in the question
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    Shweta thakur
    sir
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