Question

Title: Determination of Chloride ion concentration by titration

Introduction
Titration is a widely used method in analytical chemistry for determining the concentration of an unknown substance in a solution. One common application of titration is the determination of chloride ion concentration using Mohr's method. This technique involves the titration of a chloride-containing solution with silver nitrate as the titrant, with potassium chromate serving as an indicator for the endpoint of the reaction. The formation of a red precipitate signals the completion of the titration, allowing for the accurate measurement of chloride ion concentration. This method is crucial in various industries and laboratories for quality control and research purposes. In this study, we performed a practical demonstration of Mohr's method to determine the chloride ion concentration in a solution through silver nitrate titration.
Materials/Equipment required
The materials used for the practical included a burette with 10 and 20ml capacity, a 100ml volumetric flask, a 250ml conical flask, and 10ml and 100ml measuring cylinders.
Solution required
To prepare a 0.1 mol/L silver nitrate solution, 5g of AgNO3 was dried at 100℃ for two hours and cooled before accurately weighing out 4.25g and dissolving it in 250ml of distilled water in a conical flask. Next, a potassium chromate indicator solution (approximately 0.25mol/L) was prepared by dissolving 1g of potassium dichromate in 20ml of distilled water. Following this, an unknown solution of sodium chloride was found and prepared for use in the experiment.
Method
To determine the concentration of the unknown sodium chloride solution, a 10ml aliquot is pipetted into a conical flask and mixed with 50ml of distilled water and 1ml of chromate indicator. The solution is then titrated with 0.1mol/Silver nitrate solution. The formation of a white precipitate indicates the endpoint of the titration, while the chromate indicator initially gives the solution a faint lemon yellow color.
what would be the mass for the chloride ion was used. balance the chemical equatio and provide it

Answer 1

[AI-generated answer — Bot GPT 3.5]

To calculate the mass of chloride ion used in the titration, we need to consider the stoichiometry of the reaction between silver nitrate (AgNO3) and sodium chloride (NaCl).

The balanced chemical equation for the reaction is:
AgNO3 + NaCl → AgCl + NaNO3

From the equation, we can see that 1 mole of silver nitrate reacts with 1 mole of sodium chloride to form 1 mole of silver chloride.

Given that the molarity of silver nitrate solution used is 0.1 mol/L and the volume used is 10 ml (0.01 L), we can calculate the number of moles of silver nitrate used:
0.1 mol/L x 0.01 L = 0.001 mol

Since the reaction stoichiometry is 1:1, the number of moles of silver chloride formed is also 0.001 mol.

The molar mass of silver chloride (AgCl) is approximately 143.32 g/mol. Therefore, the mass of chloride ion present in the solution used for titration can be calculated as follows:
0.001 mol x 143.32 g/mol = 0.14332 g

So, the mass of chloride ion used in the titration would be approximately 0.14332 grams.