InterviewSolution
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InterviewSolution
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For the electrochemical cell, `Mg(s)|Mg^(2+)(aq,1 M)||Cu^(2+)(aq.1 M) Cu(s)`, the standard emf of the cell is 2.70 V at 300 K. When the concentration of `Mg^(2+)` is changed to x M, the cell potential changes to 2.67 V at 300 K. What is the value of x ? (Given, F/R =11500 K `V^(-1)`,where F is the Faraday constant and R is the gas constant, the value of `"In"_((10))(10)=2.30)`. |
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Answer» The cell reaction is : `Mg(s)+Cu^(2+)(aq)rarr Mg^(2+)(aq)+Cu(s)` According to Nernst equation `E=E^(@)-(RT)/(2F)In([Mg^(2+)])/([Cu^(2+)])` `E_(cell)^(@)=2.70 V,E_(cell)=2.67 V,Mg^(2+)=x M, Cu^(2+)=1 M` `2.67=2.70-(Rxx300)/(2F)"In "x` `-0.03=-(Rxx300)/(2F)"In "x or "In "x=((0.03)xx2)/(300)xx(F)/(R)` In `Inx=(0.03xx2xx(11500))/(300)=2.3 or x=10` |
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