Question

If a current of 1.5 A is passed for 4.00 hours through a molten tin salt and 13.3g of tin is deposited, what is the oxidation state of the metal in the salt?

(Sn = 118.7, F = 96500 C mol-1)
A. 1
B. 2
C. 3
D. 4

Answer 1

To find the oxidation state of the metal in the salt, we can use Faraday's law of electrolysis.

The amount of substance deposited at an electrode during electrolysis is directly proportional to the charge passed through the electrolyte.

The formula to calculate the amount of substance deposited is:

Amount of substance = (Charge passed / Faraday constant) * Molar mass

Charge passed = Current * Time

The given current is 1.5 A, and the given time is 4.00 hours. We need to convert the time to seconds to match the unit of the Faraday constant, which is coulombs per mole.

4.00 hours = 4.00 * 60 * 60 seconds = 14,400 seconds

Charge passed = 1.5 A * 14,400 seconds = 21,600 C

Now, we can calculate the amount of substance deposited:

Amount of substance = (21,600 C / 96500 C mol-1) * 118.7 g mol-1
Amount of substance = 26.6 g

The amount of tin deposited is given as 13.3 g. This indicates that the oxidation state of tin in the salt is 2.

Therefore, the answer is B. 2.