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For the determination of the quantity of chloride in a physiological serum sample by the Volhard method, a sample of 25.00 ml was treated with 50.00 ml of 0.110 mol/L Silver nitrate solution and the excess of silver ions was titrated with 17.00 ml of a solution of potassium thiocyanate 0.100 mol/L using a solution containing iron III ions as an indicator. What concentration of NaCl in the sample in MOL/L and g/L
To calculate the concentration of NaCl in the sample, we need to follow these steps:
Step 1: Calculate the amount of AgNO3 used in the titration:
Amount of AgNO3 = volume of AgNO3 solution (in L) * molarity of AgNO3 solution
= 50.00 ml * 0.110 mol/L
= 5.50 mmol
Step 2: Calculate the amount of KSCN used in the titration:
Amount of KSCN = volume of KSCN solution (in L) * molarity of KSCN solution
= 17.00 ml * 0.100 mol/L
= 1.70 mmol
Step 3: Calculate the amount of Cl- ions in the sample:
Amount of Cl- ions = amount of KSCN (in mmol)
Step 4: Calculate the volume of the sample in L:
Volume of sample = 25.00 ml = 0.025 L
Step 5: Calculate the concentration of NaCl in the sample:
Concentration of NaCl (in mol/L) = amount of Cl- ions (in mmol) / volume of sample (in L)
Concentration of NaCl (in mol/L) = 1.70 mmol / 0.025 L
Concentration of NaCl (in mol/L) = 68 mol/L
Step 6: Calculate the concentration of NaCl in g/L:
To convert molarity to g/L, we need to multiply the concentration by the molar mass of NaCl, which is approximately 58.44 g/mol.
Concentration of NaCl (in g/L) = concentration of NaCl (in mol/L) * molar mass of NaCl
Concentration of NaCl (in g/L) = 68 mol/L * 58.44 g/mol
Concentration of NaCl (in g/L) = 3973.92 g/L
Therefore, the concentration of NaCl in the sample is approximately 68 mol/L or 3973.92 g/L.
To determine the concentration of NaCl in the sample in mol/L and g/L, we need to consider the balanced chemical equation for the reaction between silver ions and chloride ions, also known as the Volhard method:
Ag+ + Cl- -> AgCl
From the equation, we can see that 1 mole of Ag+ reacts with 1 mole of Cl-. Therefore, the moles of Ag+ added to the sample (by the silver nitrate solution) should be equal to the moles of Cl- present in the sample.
Step 1: Calculate the moles of Ag+ added:
Given:
Volume of AgNO3 solution = 50.00 mL = 0.05000 L
Concentration of AgNO3 solution = 0.110 mol/L
Moles of Ag+ = concentration x volume
Moles of Ag+ = 0.110 mol/L x 0.05000 L
Step 2: Calculate the moles of Cl-:
Since 1 mole of Ag+ reacts with 1 mole of Cl-, the moles of Cl- would be equal to the moles of Ag+.
Moles of Cl- = 0.110 mol
Step 3: Convert moles of Cl- to concentration in mol/L:
To convert moles to concentration, we need to know the volume of the sample used. Based on the information given, the sample volume is 25.00 mL = 0.02500 L.
Concentration of Cl- in the sample = Moles of Cl- / Volume of sample
Concentration of Cl- = 0.110 mol / 0.02500 L
This gives the concentration of Cl- in the sample in mol/L.
Step 4: Convert concentration of Cl- to concentration of NaCl:
Since Cl- comes from NaCl in the sample, the concentration of NaCl would be the same as the concentration of Cl-.
Concentration of NaCl = Concentration of Cl-
This gives the concentration of NaCl in the sample in mol/L.
Step 5: Convert concentration of NaCl to g/L:
To convert moles/L to g/L, we need to know the molar mass of NaCl, which is approximately 58.44 g/mol.
Mass of NaCl = Concentration of NaCl x Molar mass of NaCl
Mass of NaCl = Concentration of NaCl x 58.44 g/mol
This gives the concentration of NaCl in the sample in g/L.
Now, you can substitute the values obtained from the calculations to get the final results for the concentration of NaCl in the sample in mol/L and g/L.