Identify which redox reactions occur spontaneously in the forward direction. check all that apply. check all that apply. 2ag+(aq)+ni(s)→2ag(s)+ni2+(aq) ca2+(aq)+zn(s)→ca(s)+zn2+(aq) 2cr(s)+3pb2+(aq)→2cr3+(aq)+3pb(s) fe(s)+mn2+(aq)→fe2+(aq)+mn(s)

A and C are spontaneous.

Explanation:

You must look up the standard reduction potentials for the half-reactions and then combine them to get the cell potentials for the reaction as written.

A. Ag⁺/Ni

2×[Ag⁺ + e⁻ ⟶ Ag ]             0.7996 V

1×Ni ⟶ Ni²⁺ + 2e⁻]             0.257   V

2Ag⁺ + Ni ⟶ 2Ag + Ni²⁺     1.057   V

E° > 0. The cell reaction is spontaneous.

B. Ca²⁺/Zn

Ca²⁺ + 2e⁻ ⟶ Ca                 -2.868  V

Zn ⟶ Zn²⁺ + 2e⁻                 0.7618 V

Ca²⁺ + Zn ⟶ Ca + Zn²⁺      -2.106   V

E° < 0. The cell reaction is not spontaneous.

C. Cr/Pb²⁺

2×[Cr ⟶ Cr³⁺ + 3e⁻]        0.744   V

3×[Pb²⁺ + 2e- ⟶ Pb]      -0.1262 V

2Cr + 3Pb²⁺ ⟶ 2Cr³⁺      0.618    V

E° > 0. The cell reaction is spontaneous.

D. Fe/Mn²⁺

Fe ⟶ Fe²⁺ + 2e-                 0.447 V

Mn²⁺ + 2e- ⟶ Mn              -1.185 V

Fe + Mn²⁺ ⟶ Fe²⁺+ Mn     -0.738 V

E° < 0. The cell reaction is not spontaneous.

Answer

A and D

trust me i took the test