Question

Determine the concentration of the standardized silver nitrate solution; show calculations for Trial 1. Calculate the average concentration of the standardized silver nitrate solution before beginning Part II. Use the Q test for any suspected bad data.

Answer 1

Standarization of AgNO3 solution

First prepare NaCl solution with known concentration.

Calculate molarity of this solution.

Take known amount of NaCl solution, say 20 ml of 0.1 M NaCl solution

Titrate it with AgNO3 solution. Say we have used 30 ml solution

Then calculation for the concentration of AgBO3 solution would be,

mols of NaCl taken = 0.1 M x 20 ml = 2 mmol

it would react with 2 mmol of AgNO3 to form 2 mmol of AgCl precipitate

AgNO3 + NaCl ---> AgCl

mols of AgNO3 = 2 mmol

molar concentration of AgNO3 solution = 2 mmol/30 ml = 0.067 M

Now repeat this procedure for few more readings

Say you have collected 10 readings.

Now for Q test, mark out the values which are very low or very high in error. Say in one case the volume of AgNO3 used was 5 ml and in other it was read as 40 ml. These are off values and can be eliminated and are bad data.

The average concentration would be thus an average of the remaining eight values of molar concentration calculated for the AgNO3 solution.