The Standard Cell Potential (E°)of a Voltaic Cell Constructed Using

The standard cell potential (E°) of a voltaic cell constructed using the cell reaction below is 0.76 V: Zn (s) + 2H⁺ (aq) → Zn²⁺ (aq) + H₂ (g)
With PH₂ = 1.0 atm and [Zn²⁺] = 1.0 M, the cell potential is 0.66 V. The concentration of H⁺ in the cathode compartment is __________ M.

A) 2.0 × 10^-2
B) 4.2 × 10^-4
C) 1.4 × 10^-1
D) 4.9 × 10¹
E) 1.0 × 10^-12