The standard reduction potentials for four hypothetical metal ion/metal half-cells are given below: E^ (A²⁺/A) = -0.40 V E^ (B³⁺/B) = 0.75 V E^ (C⁺/C) = 0.30 V E^ (D²⁺/D) = -1.20 V The maximum possible standard electromotive force (EMF) of a galvanic cell constructed by combining any two of these half-cells is x 10⁻² V . The value of x is

Step-by-step solution

To achieve the maximum standard cell potential, the galvanic cell must be constructed using the half-cell with the highest standard reduction potential as the cathode, and the half-cell with the lowest standard reduction potential as the anode. From the given data: Highest standard reduction potential (Cathode) = E^ (B³⁺/B) = 0.75 V Lowest standard reduction potential (Anode) = E^ (D²⁺/D) = -1.20 V The standard cell potential is calculated as: E^ _ cell = E^ _ cathode - E^ _ anode E^ _ cell = 0.75 - (-1.20) E^ _ ce