Question

A student wants to determine the concentration of silver ions (Ag+) in a solution. Using an Ag/Ag+ reference electrode, the student measures the cell potential to be +0.56 V when the solution is electrolyzed for 25 minutes at a constant current of 0.50 A. The volume of the solution is 150 mL. What is the concentration of silver ions in the solution in mol/L?

Answer 1

To determine the concentration of silver ions in the solution, we can use the following steps:1. Calculate the total charge  Q  passed through the solution during electrolysis.2. Determine the number of moles of silver ions  n  reduced during electrolysis.3. Calculate the concentration of silver ions in the solution.Step 1: Calculate the total charge  Q  passed through the solution during electrolysis.Q = current  I   time  t The current  I  is 0.50 A, and the time  t  is 25 minutes, which is equivalent to 1500 seconds  25  60 .Q = 0.50 A  1500 s = 750 C  Coulombs Step 2: Determine the number of moles of silver ions  n  reduced during electrolysis.Using Faraday's law, we can determine the number of moles of silver ions reduced:n = Q /  z  F where z is the number of electrons transferred per ion  for Ag+, z = 1  and F is Faraday's constant  96485 C/mol .n = 750 C /  1  96485 C/mol  = 0.00777 molStep 3: Calculate the concentration of silver ions in the solution.The volume of the solution is 150 mL, which is equivalent to 0.150 L. The concentration  C  of silver ions in the solution can be calculated as:C = n / VC = 0.00777 mol / 0.150 L = 0.0518 mol/LTherefore, the concentration of silver ions in the solution is approximately 0.0518 mol/L.