निम्न अभिक्रिया के लिए साम्य स्थिरांक की गणना कीजिए |
`Cu^(2+) + In^(2+) harr Cu^(+) + In^(3+)`
दिया गया है `E_(Cu^(2+)//Cu^(+))^(@)=0.15 V, E_(In^(2+)//In^(+))^(@) = - 0.4 V, E_(In^(3+)//In^(+))^(@) = - 0.42 V`

Explanation

`{:(Cu^(2+) + e^(-)rarr Cu^(+)","" "Delta G_(1)^(@) = - 0.15 F),(In^(2+) + e^(-) rarr In^(+)","" "DeltaG_(2)^(@)= + 0.4 F),(" "In^(+) rarr In^(3+) + 2e^(-)" "DeltaG_(3)^(@)=-0.84 F),(ulbar(Cu^(2+) + In^(2+) harr Cu^(+) + In^(3+)" "Delta G^(@) = - 0.59 F)):}`
`-nFE^(@) = - "0.59 F अथवा," -E_("सेल")^(@) F = - 0.59 F`
`therefore " "E_("सेल")^(@) = 0.59 V`
नेर्नस्ट समीकरण के अनुसार-
`E_("सेल")=E_("सेल")^(@)-(0.0591)/(n)log K_(c)`
साम्यावस्था पर-
`E_("सेल") = 0`
`therefore" "E_("सेल")^(@) = (0.0591)/(n) log K_(c)`
अत:, `0.59 = (0.0591)/(1) log K_(c)`
अथवा, `log K_(c) = (0.59)/(0.0591) = 9.983 ~~ 10`
`therefore" "K_(c) = 10^(10)`