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The emf of the following cell Mg |Mg^...

The emf of the following cell
Mg |`Mg^(+2) (0.01 M) || Sn^(+2)` (0.1 M) | Sn at 298 K in 'V' is
(Given , `E_(Mg^(+2)|Mg)^(@) = -2.34 V, E_(Sn^(+2)|Sn)^(@)` = - 0.14 V )

A

2.17

B

2.23

C

2.51

D

2.45

Text Solution

Verified by Experts

The correct Answer is:
B
At anode , `" " Mg rarr Mg^(2+) + 2e^(-)`
At cathode, `" " Sn^(2+) + 2e^(-) rarr Sn`
From Nernst equation,
`E_("cell") = E_("cell")^(@) - ( 0.0591)/(n) log ""(Mg^(+2))/(Sn^(+2)) `
`E_("cell") = -0.14 - (- 2.34 ) - (0.0591)/(2) log 10^(-1) " " (because n = 2e^(-) ) `
= ` 2.2 + (0.0591)/(2) `
` = 2.2 + 0.0295 approx 2.23`
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