Problem: Part A. Predict whether the following reactions are spontaneousPd2+(aq) + H2(g) → Pd(s) + 2 H+(aq)                Pd2+(aq) + 2 e- → Pd(s)                     E° = 0.987 VSn4+(aq) + H2(g) → Sn2+(aq) + 2 H+(aq) )        Sn4+(aq) + 2 e- → Sn2+(aq)                 E° = 0.154 VNi2+(aq) + H2(g) → Ni(s) + 2 H+(aq)                  Ni2+(aq) + 2 e- → Ni(s)                       E° = -0.25 VCd2+(aq) + H2(g) → Cd(s) + 2 H+(aq)               Cd2+(aq)  + 2 e- → Cd(s)                    E° = -0.403 VFrom your answers, decide which of the above metals could be reduced by hydrogenPart B. Identify the oxidizing agents and reducing agents in the reaction in Part A

FREE Expert Solution

For Part A, we’re being asked if the given redox reaction occurs spontaneously in the forward direction.

Recall that the greater the E°cell of a redox reaction, the more likely the reaction will occur (more spontaneous reaction)

E°cell > 0 spontaneous in the forward direction
E°cell < 0 nonspontaneous in the forward direction


We will have to calculate for the cell potential to determine the spontaneity of the redox reaction using the following steps:

Step 1. Write the two half-cell reactions 
Step 2. Identify the oxidation half-reaction (anode) and the reduction half-reaction (cathode)
Step 3. Calculate E°cell.

Recall that standard reduction potential for the Standard Hydrogen Electrode:

2 H+(aq) + 2 e- → H2(g)             E° = 0.000 V


Let's take a look at each reaction given:

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Problem Details

Part A. Predict whether the following reactions are spontaneous

Pd2+(aq) + H2(g) → Pd(s) + 2 H+(aq)                Pd2+(aq) + 2 e- → Pd(s)                     E° = 0.987 V

Sn4+(aq) + H2(g) → Sn2+(aq) + 2 H+(aq) )        Sn4+(aq) + 2 e- → Sn2+(aq)                 E° = 0.154 V

Ni2+(aq) + H2(g) → Ni(s) + 2 H+(aq)                  Ni2+(aq) + 2 e- → Ni(s)                       E° = -0.25 V

Cd2+(aq) + H2(g) → Cd(s) + 2 H+(aq)               Cd2+(aq)  + 2 e- → Cd(s)                    E° = -0.403 V

From your answers, decide which of the above metals could be reduced by hydrogen

Part B. Identify the oxidizing agents and reducing agents in the reaction in Part A

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Cell Potential concept. If you need more Cell Potential practice, you can also practice Cell Potential practice problems.