5. A solution of silver nitrate with a molar concentration of 0.1000mol/L is titrated by a solution of potassium thiocyanate with the same concentration. Calculate pAg, if to 10.00 ml of silver nitrate solution were added a) 9.90 ml; b) 10.00 ml and c) 10.1 ml of titrant.

Question

5. A solution of silver nitrate with a molar concentration of 0.1000mol/L is titrated by a solution of potassium thiocyanate with the same concentration. Calculate pAg, if to 10.00 ml of silver nitrate solution were added a) 9.90 ml; b) 10.00 ml and c) 10.1 ml of titrant.

Answer 1

To calculate the pAg of the solution, we need to determine the concentration of silver ions (Ag+) in the solution.Given information:- The molar concentration of the silver nitrate (AgNO3) solution is 0.1000 mol/L.- The molar concentration of the potassium thiocyanate (KSCN) solution is also 0.1000 mol/L.a) When 9.90 ml of KSCN solution is added to 10.00 ml of AgNO3 solution:- The total volume of the solution becomes 19.90 ml.- The concentration of Ag+ remains 0.1000 mol/L, as the volume of the AgNO3 solution is 10.00 ml.- The concentration of SCN- becomes 0.1000 mol/L, as the volume of the KSCN solution is 9.90 ml.The reaction between Ag+ and SCN- is:Ag+ + SCN- ⇌ [AgSCN]The equilibrium constant (K) for this reaction is:K = [AgSCN] / ([Ag+] × [SCN-])Since the concentrations of Ag+ and SCN- are equal, the equilibrium constant can be simplified to:K = 1The pAg is defined as the negative logarithm of the concentration of Ag+:pAg = -log[Ag+]Since the concentration of Ag+ is 0.1000 mol/L, the pAg is:pAg = -log(0.1000) = 1b) When 10.00 ml of KSCN solution is added to 10.00 ml of AgNO3 solution:- The total volume of the solution becomes 20.00 ml.- The concentration of Ag+ becomes 0.0500 mol/L, as the volume of the AgNO3 solution is halved.- The concentration of SCN- becomes 0.1000 mol/L, as the volume of the KSCN solution is 10.00 ml.Using the same equilibrium constant (K = 1) as in part a), the pAg is:pAg = -log(0.0500) = 1.3c) When 10.1 ml of KSCN solution is added to 10.00 ml of AgNO3 solution: solution becomes 20.10 ml.- The concentration of Ag+ remains 0.1000 mol/L, as the volume of the AgNO3 solution is 10.00 ml.- The concentration of SCN- becomes 0.0980 mol/L, as the volume of the KSCN solution is 10.1 ml.Using the same equilibrium constant (K = 1) as in part a), the pAg is:pAg = -log(0.0980) = 0.9Therefore, the correct answer is:a) pAg = 1b) pAg = 1.3c) pAg = 0.9

Вопрос

5. A solution of silver nitrate with a molar concentration of 0.1000mol/L is titrated by a solution of potassium thiocyanate with the same concentration. Calculate pAg, if to 10.00 ml of silver nitrate solution were added a) 9.90 ml; b) 10.00 ml and c) 10.1 ml of titrant.

Решения

Ответ