`25^(@)C` पर एक गैल्वैनिक सेल में अर्द्ध-सेल अभिक्रियाएँ निम्न प्रकार होती हैं
`Al//Al^(3+)(0.001 M) || Ni^(2+)(0.50 M //Ni`
यदि `E^(0)_(Ni^(2+)//Ni) = -0.25 V`
`E^(0)_(Al^(3+)//Al) = -1.66 V`

Explanation

यदि अभिक्रिया है `2Al + 3Ni^(2+) rarr 2Al^(3+) + 3Ni`
`E_(cell) = E^(0)_(C) - E^(0)_(A) + 0.059/n log [Al]^(2)[Ni^(2+)]^(3)/([Al^(3+)]^(2)[Ni]^(3))`
`(E^(0)_(Ni^(2+)//Ni) - E^(0)_(Al^(3+)//Al)) + 0.059/n log [Ni^(2+)]^(3)/([Al^(3+)]^(2))`
[Al] = [Ni] = 1
`[-0.25 - (-1.66)] + 0.059/6 log (0.50)^(3)/(0.001)^(2)`
` = (-0.25 + 1.66) + 0.059/6 log 0.5 xx 0.5 xx 0.5/(0.001 xx 0.001)`
`1.41 + 0.059/6 log(5)^(3) xx 10^(3)`
`1.41 + 0.059/6 xx 3 [log50]`
` = 1.41 + 0.059/2 xx 1.699 = 1.41 + 0.050 = 1.46 V`