Question

Electroplating

It takes 135.6 s for a 1.31-A current to plate 0.1907 g of a metallic element from a solution containing M²⁺ ions.

What is the element (M)? Answer with the chemical symbol for the element.

Answer 1

Answer 2

To determine the element (M), we need to use Faraday's Law of Electrolysis, which relates the amount of a substance produced at an electrode to the electric current and the time.

The equation is:

moles of M = (current x time) / (Faraday's constant x Molar mass of M)

First, we need to calculate the number of moles of M produced:

moles of M = (1.31 A x 135.6 s) / (96500 C/mol x n)

where n is the number of electrons transferred per ion during the electrolysis. We don't know the value of n yet, so we can leave it as a variable for now.

Next, we need to calculate the molar mass of M:

molar mass of M = mass of M / moles of M

We are given the mass of M produced (0.1907 g), so we can plug in the values and solve for the molar mass:

molar mass of M = 0.1907 g / moles of M

Now we can use the periodic table to find the element that has this molar mass. The closest match is silver (Ag), which has a molar mass of 107.87 g/mol.

So we have:

molar mass of M ≈ 0.1907 g / moles of M

molar mass of M ≈ 107.87 g/mol

Finally, we can solve for n using the oxidation state of the ion in the solution. Since we don't have that information, we can't determine n with certainty. However, for most common metallic elements, the oxidation state is either +1 or +2, which means that n is either 1 or 2. Using n = 1 and n = 2, we get:

n = 1: moles of M = (1.31 A x 135.6 s) / (96500 C/mol x 107.87 g/mol)

moles of M ≈ 0.000152

n = 2: moles of M = (1.31 A x 135.6 s) / (96500 C/mol x 2 x 107.87 g/mol)

moles of M ≈ 0.000305

The closest match to either value is silver (Ag), which has an oxidation state of +1 or +2, so the answer is:

M = Ag (silver)