Question

1.18 1.67 1.20 V C104 C1O; HCIO HCIO 1.63 1.36 + Cl - C1 The above potentials in the Latimer diagram are all at pH = 0. 1. What is the standard potential for the reduction of CIO4 to Cl' at pH =0? (3 pts) 2. What is the standard potential for the reduction of CIO4 to Cl' at pH =4? (3pts) (Hint: use the Nernst equation) 3. Is the disproportionation reaction of Cl2 thermodynamically spontaneous at pH 0? (2 pts) Write a balanced reaction and calculate the voltage to justify your answer. (3 pts)

Answer 1

The standard potential for the reduction from ClO4- to Cl- can be calculated from a Latimer diagram at pH = 0, and altered for pH = 4 using the Nernst equation. Disproportionation of Cl2's spontaneity at pH = 0 is determined by assessing the overall cell potential from half-reactions.

Step-by-step explanation:

The standard potential for the reduction of ClO4- to Cl- at pH = 0 can be determined using the given Latimer diagram's potentials. It involves summing the individual reduction potentials that lead from ClO4- to Cl-. The Nernst equation is employed to calculate the standard potential at pH = 4, considering the effects of pH on reduction potential.

The disproportionation reaction of Cl2 involves the element in both oxidation and reduction states. It can occur if the combined potential for these half-reactions is positive. To justify the thermodynamic spontaneity, we need to write a balanced half-reaction for both oxidation and reduction, and calculate the standard cell potential (Ecell). If Ecell is positive, the reaction is spontaneous under standard conditions.

Answer 2

The standard potential for the reduction of CIO4 to Cl' at pH = 0 is 1.20 V. The standard potential for the reduction of CIO4 to Cl' at pH = 4 cannot be determined without additional information. The spontaneity of the disproportionation reaction of Cl2 at pH 0 cannot be determined without the standard potentials.

Step-by-step explanation:

The Latimer diagram provided shows the potentials for different species at pH = 0. To find the standard potential for the reduction of CIO4 to Cl' at pH = 0, we look at the reduction half-reaction of CIO4 to Cl' and find its potential on the Latimer diagram. From the diagram, we can see that the potential for the reaction CIO4 + 2H+ + 2e- -> Cl' + 2HClO is 1.20 V. Therefore, the standard potential for the reduction of CIO4 to Cl' at pH = 0 is 1.20 V.

For the standard potential at pH = 4, we need to use the Nernst equation. The Nernst equation relates the standard potential to the concentration of the species and the pH of the solution. The equation is E = E° - (0.0592/n)log(Q), where E is the potential at a given pH, E° is the standard potential, n is the number of electrons transferred in the reaction, and Q is the reaction quotient. In this case, the reaction quotient is [Cl-][HClO]/[H+][ClO4-]. We can calculate the value of Q using the given concentrations and pH, and then use the Nernst equation to find the potential. However, the question does not provide the concentrations of the species or the value of Q, so we cannot determine the standard potential at pH = 4 without that information.