MHT CET202522 Apr 2025Morning ShiftChemistryElectrochemistryActual
If standard reduction potential ( E ^ ) of ( +2 Ni _ ( aq ) Ni _ ( s ) ) and ( ( aq ) +3 Al Al _ ( s ) ) are -0.25 V and -1.66 V respectively. What is standard emf of cell reaction 2 Al _ ( s ) +3 Ni _ ( aq ) ⁺² 2 Al _ ( aq ) ⁺³+3 Ni _ ( s )
Options
- A+2.57 ~V
- B-2.57 ~V
- C+1.41 ~V
- D-1.91 ~V
Correct answer
C. +1.41 ~V
Step-by-step solution
Standard EMF of the cell reaction The cell reaction is 2 Al _ ( s ) + 3 Ni _ ( aq ) ⁺² 2 Al _ ( aq ) ⁺³ + 3 Ni _ ( s ) . Aluminum is oxidized at the anode, Al Al ⁺³ + 3 e ⁻ , and nickel is reduced at the cathode, Ni ⁺² + 2 e ⁻ Ni . Given standard reduction potentials: E ^ ( Ni ⁺² | Ni ) = -0.25 V and E ^ ( Al ⁺³ | Al ) = -1.66 V . The cell EMF is calculated as E ^ _ cell = E ^ _ cathode - E ^ _ anode = (-0.25) - (-1.66) = +1.41 V . E ^ _ cell = +1.41 V .