Question

4M solution of AgNO₃ is electrolysed using Ag electrodes. A current of 3 amphere is passed 9.68x10³ sec . The molarity of solution after electrolysis is Assume there is no change in the volume of solution).

Answer 1

The molarity of the 4M AgNO₃ solution after electrolysis, with 3 amperes passed through for 9.68 x 10³ seconds assuming no change in volume, is calculated to be 3.698 M.

Step-by-step explanation:

The student is asking about the change in molarity of a 4M AgNO₃ solution after electrolysis with Ag electrodes when a total charge of 3 A is passed through the solution for 9.68 x 10³ seconds. To answer this question, we apply Faraday's laws of electrolysis to convert the current and time into moles of electrons, then use stoichiometry to relate moles of electrons to moles of Ag+ consumed, and finally adjust the molarity based on the moles of AgNO₃ that remain.

To calculate moles of electrons, we multiply the current (in amperes) by the time (in seconds) and divide by Faraday's constant (96,485 coulombs per mole of electrons):

(3 A) × (9.68 x 10³ s) / (96,485 C/mol) = 0.302 moles of electrons,

Since each mole of Ag requires one mole of electrons to be reduced (Ag+ + e⁻ → Ag), 0.302 moles of Ag+ are reduced. Therefore, 0.302 moles of AgNO₃ are consumed.

The initial moles of AgNO₃ in solution can be calculated as:

(4 mol/L) × (1 L) = 4 moles of AgNO₃,

After reduction, the remaining moles of AgNO₃ are:

4 moles - 0.302 moles = 3.698 moles of AgNO₃.

Assuming no change in volume, the new molarity of the solution after electrolysis becomes:

3.698 moles / 1 L = 3.698 M.