Which of these redox reactions is spontaneous as written?
a. Ni + Zn2+ → Ni2+ + ZnB. Mg + Li+ → Mg2+ + LiC. Cu + Au3+ → Cu2+ + AuD. Zn + Ca2+ → Zn2+ + Ca?

Respuesta :

D. Zn + Ca²⁺ → Zn²⁺ + Ca

Because Ca is more active metal (from the electrochemical series).