Identify the reaction from having top position in EMF series according to their electrode potential at 298k

Options

A. `Fe^(2+) + 2e^(-) to Fe(s)`
B. `Au^(3+) + 3e^(-) to Au(s)`
C. `K^(+) + "1e"^(-) to K(s)`
D. `Mg^(2+) + 2e^(-) to Mg(s)`

Answer

B

Explanation

`Au^(3+) + 3e^(-) to Au(s), E^(@) = 1.40 V`
`Fe^(2+) + 2e^(-) to Fe(s), E^(@) =-0.44 V`
`Mg^(2+) + 2e^(-) to Mg(s) E^(@) to -2.36 V`
`K^(+) + 1e^(-) to K(s) E^(@) =-2.93 V`
`Au^(3+)` occupies the top position in the electrochemical series.