D. Pure copper rod acts as a cathode. Given that the standard reduction potential for Fe3+/Fe2+= 0.77 V and I2/I−= 0.54V.

The normal reaction would be: hemoglobin [Hb(Fe2+) + O2 Oxyhemoglobin [Hb(Fe2+)O2] Sometimes, however, the hemoglobin is oxidized in the body to methemoglobin [Hb(Fe3+)], which is unable to carry ...