Faraday¡¯s Law of Electrolysis

• Practice Problem.
• What is the oxidation state of the osmium atom
in an unknown salt if 26.7 grams of osmium plate
out when a current of 15 amps is passed through
a solution of this salt for 1 hour?

Coulombs = A x seconds = 15 x 60 x 60 = 54000.

1F = 96,485 coulombs will plate out 190.2g/valence.

You had 54,000 C which is
54,000/96485 C = 0.5597 moles.
moles x valence/molar mass = 26.7*valence/190.2 = 0.5597
Solve for valence . My calculator reads 3.98 which I would round to 4.

To find the oxidation state of the osmium atom in the unknown salt, we need to apply Faraday's law of electrolysis.

Faraday's law states that the amount of substance deposited or liberated during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte.

The formula to calculate the amount of substance deposited is:

Amount of substance = (Current × Time) / (Faraday's constant × Equivalent weight)

First, let's find the equivalent weight of osmium.

The equivalent weight (Eq. wt) of a substance is the molar mass divided by the number of electrons transferred during the redox reaction.

The molar mass of osmium (Os) is approximately 190.2 g/mol. In this case, since osmium plates out, it is gaining electrons, so the number of electrons transferred is equal to the magnitude of the charge of osmium in the salt.

To find the oxidation state of osmium, we need to know the charge of the anion in the salt, which is not provided in the problem. Therefore, we cannot determine the oxidation state of osmium without additional information about the salt.

However, we can still calculate the amount of substance deposited using the given information:

Current = 15 Amps
Time = 1 hour = 3600 seconds (since 1 hour = 60 minutes × 60 seconds)
Faraday's constant = 96,485 C/mol (charge of 1 mole of electrons)

Using the formula above, we can substitute the values and solve for the amount of substance deposited:

Amount of substance = (15 A × 3600 s) / (96,485 C/mol × Eq. wt)

Please provide the charge on the anion in the salt, and I can help you calculate the amount of substance deposited.

To determine the oxidation state of an osmium atom, we need to make use of Faraday's law of electrolysis. Faraday's law states that the amount of substance produced or consumed during an electrolysis process is directly proportional to the quantity of electricity passed through the electrolyte.

To solve this problem, we will need to follow these steps:

Step 1: Calculate the charge passed through the solution.
- The formula to calculate the charge (Q) is given by Q = I * t, where I is the current in amperes and t is the time in seconds.

Given:
- Current (I) = 15 amps
- Time (t) = 1 hour = 3600 seconds

Calculating the charge:
Q = 15 amps * 3600 seconds = 54000 coulombs (C)

Step 2: Convert the charge (Q) to moles of electrons passed.
- 1 Faraday (F) is equal to the charge of 1 mole of electrons, which is approximately 96,485 C.
- The formula to convert charge (Q) to moles (n) is given by n = Q / F.

Calculating the moles of electrons passed:
n = 54000 C / 96485 C/mol ≈ 0.559 moles

Step 3: Determine the molar ratio between osmium and electrons.
- The balanced equation for the electrolysis of the unknown salt is needed to establish the molar ratio.
- Since the equation is not provided, we will assume a simple one-to-one ratio between the osmium atoms and the electrons.

The molar ratio between osmium and electrons is 1:1.

Step 4: Calculate the molar mass of osmium (Os).
- The molar mass of osmium is needed to convert the moles of electrons to grams of osmium.

The molar mass of osmium (Os) = 190.23 g/mol

Step 5: Convert moles of electrons to grams of osmium.
- The formula to convert moles (n) to grams (m) is given by m = n * M, where M is the molar mass.

Calculating the grams of osmium:
m = 0.559 moles * 190.23 g/mol ≈ 106.4 grams

Thus, approximately 106.4 grams of osmium plate out when a current of 15 amps is passed through the solution for 1 hour.