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This method uses a back titration with potassium thiocyanate to determine the concentration of chloride ions in a solution.
Before the titration an excess volume of a standardized silver nitrate solution is added to the solution containing chloride ions, forming a precipitate of silver chloride (AgCl). The term 'excess' is used as the moles of silver nitrate added are known to exceed the moles of sodium chloride present in the sample so that all the chloride ions present will react.
Ag+ + Cl- AgCl(s) (Ksp = 1.70 × 10−10)
Excess White
Excess of Ag+ is back titrated with SCN-.
Back titration is used in the Volhard method when the analyte interferes with the primary titration method. This allows for the determination of the interfering substance before the main titration is carried out. It provides more accurate results by isolating the interfering substance and ensuring that it does not affect the primary titration.
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What is a volhard method?
The Volhard method is a chemical titration method used to determine the concentration of halide ions, such as chloride, bromide, or iodide, in a sample. It involves adding a silver nitrate solution to the sample to form a precipitate, which is then back-titrated with a standard solution of thiocyanate ion to determine the halide concentration.
What is a back titration?
A back titration is a technique used in analytical chemistry to determine the concentration of an analyte by reacting it with an excess of a known reagent, then back-titrating the remaining excess reagent. This method is useful when the analyte reacts slowly or incompletely with the titrant in a direct titration.
What are the two indirect method of titration?
The two indirect methods of titration are back titration and reverse titration. In back titration, an excess of a reagent is added to react with the analyte, and then the unreacted excess is titrated to determine the amount that reacted with the analyte. In reverse titration, a standard solution is first added to a known amount of analyte to react completely, and then the excess standard solution is titrated back to determine the amount that reacted with the analyte.
What are complexometric titration method?
Complexometric titration is a type of volumetric analysis used to determine the concentration of metal ions in a solution by forming complexes with a specific reagent. In this method, a chelating agent is typically used to form a stable complex with the metal ion, and the endpoint of the titration is usually determined using a colorimetric indicator or a pH meter. This technique is commonly employed in the analysis of a variety of metal ions in solution.
Does it take more NaOH in back titration with phenolphthalein?
Yes, it takes more NaOH in a back titration with phenolphthalein compared to a direct titration because the indicator reacts with the excess acid in the sample before the endpoint is reached. This means more base is required to neutralize the excess acid present.
What is a volhard method?
The Volhard method is a chemical titration method used to determine the concentration of halide ions, such as chloride, bromide, or iodide, in a sample. It involves adding a silver nitrate solution to the sample to form a precipitate, which is then back-titrated with a standard solution of thiocyanate ion to determine the halide concentration.
What is a back titration?
A back titration is a technique used in analytical chemistry to determine the concentration of an analyte by reacting it with an excess of a known reagent, then back-titrating the remaining excess reagent. This method is useful when the analyte reacts slowly or incompletely with the titrant in a direct titration.
What are the two indirect method of titration?
The two indirect methods of titration are back titration and reverse titration. In back titration, an excess of a reagent is added to react with the analyte, and then the unreacted excess is titrated to determine the amount that reacted with the analyte. In reverse titration, a standard solution is first added to a known amount of analyte to react completely, and then the excess standard solution is titrated back to determine the amount that reacted with the analyte.
What is the chemical process for back titration?
In back titration, a known excess of a reagent is added to react with the analyte. After the reaction is complete, the amount of excess reagent is determined by titration with another reagent. The difference between the initial amount of excess reagent and the amount required in the back titration is used to determine the amount of analyte present.
What are complexometric titration method?
Complexometric titration is a type of volumetric analysis used to determine the concentration of metal ions in a solution by forming complexes with a specific reagent. In this method, a chelating agent is typically used to form a stable complex with the metal ion, and the endpoint of the titration is usually determined using a colorimetric indicator or a pH meter. This technique is commonly employed in the analysis of a variety of metal ions in solution.
What is Back titration?
A back titration is a form of titraiton in which an excess of standard reagent is added and then the reverse of the titration is carried out.
Does it take more NaOH in back titration with phenolphthalein?
Yes, it takes more NaOH in a back titration with phenolphthalein compared to a direct titration because the indicator reacts with the excess acid in the sample before the endpoint is reached. This means more base is required to neutralize the excess acid present.
What difference between titration and back titration?
In titration, a solution of known concentration is added to a solution of unknown concentration until the reaction reaches its endpoint, allowing the unknown concentration to be calculated. In back titration, an excess of a reagent is added to the analyte, and the unreacted excess is then titrated with a titrant to determine the amount of excess reagent that reacted with the analyte.
When should back titration used instead of back titration?
when we do not know nothing about the other titrant.
Explain the technique of back titration?
Back titration is a technique used in analytical chemistry to determine the concentration of an analyte by reacting it with an excess of a known reagent, then back-titrating the unreacted excess with another reagent. This method is useful when direct titration is not feasible due to issues such as slow reaction kinetics or interference from impurities. By analyzing the amount of excess reagent that reacted, the initial concentration of the analyte can be calculated.
When to use back-titration instead of direct titration?
Back-titration is useful when the analyte reacts slowly or not at all with the indicator used in direct titration. It is also used when the endpoint of the direct titration is not clearly visible. Additionally, back-titration is employed when the analyte is present in very low concentrations and requires a larger amount of titrant for direct titration.
Why back titration is used in complexometric titration?
Back titration is used in complexometric titration when the analyte reacts slowly with the titrant or when a direct titration is not feasible due to interference from other substances. By adding an excess of a known reagent to react with the analyte, followed by titration with another reagent to determine the excess, the concentration of the analyte can be accurately calculated.
