Question

निम्नलिखित अभिक्रियाओं वाले सेल का मानक सेल - विभव परिकलित कीजिए -
(i) `2Cr_((s))+3Cd_((aq))^(2+)to2Cr_((aq))^(3+)+3Cd`
(ii) `Fe_((aq))^(2+)+Ag_((aq))^(+)toFe_((aq))^(3+)+Ag_((s))`
उपरोक्त अभिक्रियाओं के लिए `Delta_(r)G^(@)` एवं स्थिरांक की भी गणना कीजिए ।
दिया है
`E_(Cr^(3+),Cr)^(@)=-0.74V,E_(Cd^(3+),Cd)^(@)=-0.40V,E_(Ag^(+)//Ag)^(@)=0.80V,E_(Fe^(3+)//Fe^(2+))^(@)=0.77V`

Answer 1

(i) `E_("Cell")^(@)=E_("cathode")^(@)-E_("anode")^(@)`
`=-0.40-(-00.74)=+0.34V`
`Delta_(r)G^(@)=-nFE_("cell")^(@)`
`=-6xx196860"J mol"^(-1)=-196.86"KJ mol"^(-1)`
`Delta_(r)G^(@)=-2.303RTlogK_(c)`
`-196860=-2.303xx8.314xx298logK_(c)`
या `logK_(c)=34.5014`
`:." "K_(c)="antilog"34.5014=3.192xx10^(34)`
(ii) `E_("Cell")=+0.80-0.77=+0.03V`
`Delta_(r)G^(@)=-nFE_("Cell")^(@)=-1xx96500xx(0.03)`
`=-2895CVmol^(-1)=-2895Jmol^(-1)`
`=-2.895KJmol^(-1)`
`Delta_(r)G^(@)=-2.303RTlogK_(c)`
`-2895=-2.303xx8.314xx298xxlogK_(c)`
या `logK_(c)=0.5074`
`K_(c)="antilog"(0.5074)=3.22`