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1. find E° values for each half reaction from the SRP tables

2. write out the overall net ionic equation
3. find the Q value (use the pressure of Cl₂ for reactant side i.e. Q = (0.20)²(0.010)/ 1atm)
4. find E° of the reaction
5. solve for E using the NERNST equation at non-standard conditions
6. solve for K using Keq = e^+(nFE°/RT)

1 Answer

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Final Answer:

1. Find
\(E^o\) values:

  • Look up the standard reduction potential
    (\(E^o\)) values for the reduction and oxidation half-reactions from the SRP tables.
  • For example, assume
    \(E^o_{\text{red}} = 0.80 \, \text{V}\) and \(E^o_{\text{ox}} = 1.20 \, \text{V}\).

2. Write out the overall net ionic equation:

  • Combine the oxidation and reduction half-reactions, ensuring that the number of electrons is balanced. In this example, it might be:

  • \[ \text{Cl}_2(g) + 2\text{H}^+(aq) + 2\text{e}^- \rightarrow 2\text{Cl}^-(aq) + \text{H}_2(g) \]

3. Find the Q value:

  • Using the provided formula:
    \(Q = \frac{[\text{Cl}^-]^2}{[\text{H}^+]^2}\) based on the stoichiometry of the reaction and the given pressure conditions.

4. Find
(\(E^o\)) of the reaction:

  • Subtract
    \(E^o_{\text{ox}}\) from \(E^o_{\text{red}}\): \(E^o_{\text{reaction}} = E^o_{\text{red}} - E^o_{\text{ox}}\).

5. Solve for E using the Nernst equation at non-standard conditions:


  • \(E = E^o - (0.0592)/(n) \log(Q)\), where n is the number of moles of electrons transferred.

6. Solve for K using
\(K_(eq) = e^{((nFE^o)/(RT))}\):

  • Plug in the values for n, F,
    \(E^o\), R, and T to calculate the equilibrium constant.

Step-by-step explanation:

Let's assume that you are interested in the following half-reactions for the oxidation and reduction of chlorine gas:

Oxidation:
\( \text{Cl}_2(g) \rightarrow 2\text{Cl}^-(aq) \)

Reduction:
\( \text{2H}^+(aq) + \text{2e}^- \rightarrow \text{H}_2(g) \)

Now, let's find the standard reduction potential
(\(E^o\)) values for these half-reactions from the standard reduction potential (SRP) tables. Please note that the values may vary depending on the source of your SRP tables.

1. Find
(\(E^o\)) values:

- Look up the
\(E^o\) value for the reduction half-reaction involving
\( \text{2H}^+(aq) + \text{2e}^- \rightarrow \text{H}_2(g) \).

- Look up the
\(E^o\) value for the oxidation half-reaction involving
\( \text{Cl}_2(g) \rightarrow 2\text{Cl}^-(aq) \).

2. Write out the overall net ionic equation:

Combine the oxidation and reduction half-reactions to form the overall net ionic equation.

3. Find the Q value:

Use the provided formula to calculate Q at the given conditions.

4. Find
(\(E^o\)) of the reaction:

Subtract the
(\(E^o\)) value of the oxidation half-reaction from the
(\(E^o\)) value of the reduction half-reaction.

5. Solve for E using the Nernst equation at non-standard conditions:


\(E = E^o - (0.0592)/(n) \log(Q)\), where n is the number of moles of electrons transferred.

6. Solve for K using
\(K_(eq) = e^{((nFE^o)/(RT))}\), where F is the Faraday constant, R is the ideal gas constant, and T is the temperature in Kelvin.

User Ben Harrison
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