Silver Nitrate And Ammonium Thiocyanate

A standard solution is a solution that contains a precisely known concentration of an element or compound in analytical chemistry. To make a specific volume, a known weight of solute is dissolved. A standard substance, such as a primary standard, is used to make it. Standard solutions, such as titration solutions, are used to determine the amounts of other chemicals.

Standard solution concentrations are typically reported in mol/L, sometimes shortened to M, which stands for Morality, mol/dm3 (moles per cubic decimeter), kmol/m3 (kilomoles per cubic metre), or other terms comparable to that are used in certain titrations. The simple standard solution can be achieved by the dilution of either a single element or a compound element in a soluble solvent. The main factor is a reagent, that is ultrapure, stable, devoid of hydration fluids, and has a high molecular weight. Sodium carbonate is one of the most common acid titration standards.

In this post, we will throw some light on the mechanisms for preparing silver nitrate and ammonium thiocyanate solutions and how to standardize silver nitrate solutions and ammonium thiocyanate solutions.

 What Methods Involve The Titration Between Silver Nitrate And Ammonium Thiocyanate

• Volhard’s method is involved in the titration between silver nitrate and ammonium thiocyanate. It is a form of precipitation titration which is utilised for determining the concentration of silver in a standard solution of potassium thiocyanate.
• The titration is performed in an acidic solution. The iron indicator and the first excess of titrant react to form a red and soluble complex after the precipitation of silver as white silver thiocyanate. This technique is often employed for silver and chloride titrations, because it can be done in an acidic solution
• Volhard’s approach was first revealed in 1874 by German physicist Jacob Volhard. In acidic settings, this technique uses silver ions to determine halide ions (F, Cl, Br, I) and anions such as phosphates and chromates.

Reagents

• Silver Nitrate: Dissolve 0.895g silver nitrate in 2 mL water, then dilute with strong nitric acid to 100 mL. For the Volhard titration method, the solution is kept in a brown bottle.
• Ammonium Thiocyanate: Take ammonium thiocyanate (NH4SCN) in a flask, 100 mL water, and whirl to dissolve the NH4SCN. Filter the solution through a toughened filter paper or another suitable medium once it’s finished. Mix the clear filtrate with 1 litre of water. Keep the solution in a glass bottle with a tight lid.
• Ferric Alum: For the Volhard titration method, dissolve 5gm of ammonium ferric sulphate in roughly 20 mL of water and then makeup to 100 mL with double distilled water.

 How To Prepare Silver Nitrate Solution

1. Take 1000 mL of clean and dry volumetric flask and fill it with 100 mL of water.
2. Add around 17 gm of Silver Nitrate and stir the solution.
3. Now add 700 mL of distilled water, and mix the solution thoroughly.
4. Fill the volumetric flask to mark with distilled water, remove the funnel, close the volumetric flask with the lid, and gently shake to mix the solution.
5. Fill a suitable container with the prepared solution and label it with the relevant information.

 How To Prepare Ammonium Thiocyanate Solution

1. Take 100 mL of water in a flask and add 7.8 gm of Ammonium Thiocyanate, and swirl to dissolve it.
2. When you are done mixing the solution, filter it through a hardened filter paper.
3. Now dilute the filtrate with 1 litre of water and mix it thoroughly.
4. Store the solution tightly in a glass bottle.

After understanding the mechanisms for preparing silver nitrate and ammonium thiocyanate solutions, let’s now under how to standardize silver nitrate solution and ammonium thiocyanate solution.

Standardisation Of Silver Nitrate Solution

1. Weigh roughly 0.1g sodium chloride, which has been dried at 110 degrees Celsius for 2 hours, and dissolve in 5 mL water.
2. Now add glacial acetic acid (5 mL), eosin solution (0.15 mL), and methanol (50 mL).
3. Titrate with silver nitrate solution until the endpoint is purple, stirring constantly.
4. Calculate the Molarity Factor after doing a duplicate.
5. Keep in an amber bottle with a well-fitting, appropriate stopper to keep out atmospheric carbon dioxide.

Standardisation Of Ammonium Thiocyanate Solution

1. Add water (25 mL), ammonium iron sulphate (2 mL), and 2M nitric acid (2 mL) to silver nitrate (20 mL).
2. Titrate the solution with ammonium thiocyanate unless a reddish yellow color appears.
3. 7.612 mg of NH4SCN is comparable to 1 mL of 0.1M silver nitrate.
4. Make a copy and figure out the molarity factor.
5. Make a note of the average value.
6. Follow the general method for storing and labelling. 

Conclusion

Here, we studied how to standardise silver nitrate solution and ammonium thiocyanate solution. Volhard’s method is a back titration method that involves adding an excess of a silver nitrate standard solution to a chloride-containing sample solution. The surplus silver is then back-titrated with ferric ion as an indicator in a standardised potassium or ammonium thiocyanate solution.

The Volhard chloride estimation method is used in the Volhard titration method, and the protein is oxidised using the open Carius method with a solution in strong nitric acid. The surplus silver nitrate is then titrated with standard thiocyanate using ferric alum as the indicator, while the organic matter is eliminated and the chloride precipitates.