Question

An electrochemical cell is composed of pure nickel and pure iron electrodes immersed in solutions of their divalent ions. If the concentrations of Ni2+ and Fe2+ ions are 0.002 M and 0.40 M, respectively, what voltage is generated at 25°C? (The respective standard reduction potentials for Ni and Fe are −0.250 V and −0.440 V.) (A) −0.76 V (B) −0.26 V (C) +0.12 V (D) +0.76 V

Answer 1

Answer:C 0.12 V

Step-by-step explanation:

Given

Concentration of
`Fe^(2+) M_1=0.40 M`

Concentration of
`Ni^(2+) M_2=0.002 M`

Standard Potential for Ni and Fe are
`V_2=-0.25 V` and
`V_1=-0.44 V`

`\Delta V=V_2-V_1-(0.0592)/(2)\log ((M_1)/(M_2))`

`\Delta V=-0.25-(-0.44)-(0.0592)/(2)\log ((0.4)/(0.002))`

`\Delta V=0.12\ V`