दिया है `E_(Cr^(3+)//Cr)^(@)=-0.72V,E_(Fe^(2+)//Fe)^(@)=-0.42V` सैल `Cr|Cr_((0.01M))^(3+)||Fe_((0.01M))^(2+)|Fe` का विभव होगा

Options

A. `0.26V`
B. `0.399V`
C. `-0.399V`
D. `-0.26V`

Answer

A

Explanation

`Cr|Cr_((0.1M))^(3+)||Fe_((0.01M))^(2+)|Fe`
ऑक्सीकरण (अर्द्ध-सैल)
`CrrarrCr^(3+)+3e^(-)]xx2`
अपचयन (अर्द्ध-सैल)
`therefore Fe^(2+)+2e^(-)rarrFe]xx3`
परिणामी सैल अभिक्रिया
`2Cr+3Fe^(2+)rarr2Cr^(3+)+3Fe,n=6`
`E_("सैल")^(@)=E_("ऑक्सीकरण")^(@)+E_("अपचयन")^(@)`
`=0.72=0.42=0.30V`
`E_("सैल")=E_("सैल")^(@)-(0.0591)/(n)log.([Cr^(3+)]^(2))/([Fe^(2+)]^(3))`
`=0.30-(0.0591)/(6)log.((0.1)^(2))/((0.01)^(3))`
`=0.30-(0.0591)/(6)log.(10^(-2))/(10^(-6))`
`=0.30-(0.0591)/(6)log10^(4)`
`E_("सैल")=0.2606V`