
Chemistry: The Molecular Science
5th Edition
ISBN: 9781285199047
Author: John W. Moore, Conrad L. Stanitski
Publisher: Cengage Learning
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Please answer question 20 Part A
![**Precipitation Titration Using the Mohr Method**
An example of a precipitation titration reaction is the Mohr method, used to find the concentration of halide ions in solution, particularly Cl⁻ and Br⁻. First, the sample is analyzed by titration with a AgNO₃ solution, resulting in the precipitation of a white silver solid (e.g., AgCl). It is difficult to visually detect when all the halide ions have reacted with the silver ions, so a small amount of an indicator ion, CrO₄²⁻, is added. Because Ag₂CrO₄ is more soluble than AgCl, Ag₂CrO₄ precipitates out only after all the Cl⁻ ions have been precipitated as AgCl. Thus, when all Cl⁻ ions have reacted, Ag₂CrO₄ precipitation begins, marking the equivalence point with a rust-colored precipitate.
**Real-World Application in Food Chemistry**
As a food chemist for a major potato chip company, you are tasked with determining the salt content of new products for labeling. Potato chips are seasoned with table salt, NaCl. You weigh a handful of chips, boil them in water to extract salt, and filter the boiled chips to remove solid pieces. The chip filtrate is analyzed for Cl⁻ concentration using the Mohr method.
1. Prepare a silver nitrate solution, AgNO₃.
2. Titrate it against 0.500 g of KCl using the Mohr method. It takes 61.2 mL of AgNO₃ titrant to reach the equivalence point.
3. Use the same solution to analyze the chip filtrate in another Mohr reaction. A rusty brown precipitate forms when 46.2 mL of titrant is added.
**Part A**
If the chip sample used for the filtrate weighed 83.5 g, calculate the NaCl present in one serving (115 g) of chips. Express your answer to three significant figures with appropriate units. Enter the result in the provided field for "salt/serving."
- [Use the calculation feature to enter your answer]
This educational exercise demonstrates the practical application of the Mohr method in analytical chemistry for real-world food product analysis.](https://content.bartleby.com/qna-images/question/ded90a0e-1aa2-42d3-8902-387fb21746ad/f81907a9-b42d-4963-b10c-14c78fa8d5c9/89hxrrj_thumbnail.png)
Transcribed Image Text:**Precipitation Titration Using the Mohr Method**
An example of a precipitation titration reaction is the Mohr method, used to find the concentration of halide ions in solution, particularly Cl⁻ and Br⁻. First, the sample is analyzed by titration with a AgNO₃ solution, resulting in the precipitation of a white silver solid (e.g., AgCl). It is difficult to visually detect when all the halide ions have reacted with the silver ions, so a small amount of an indicator ion, CrO₄²⁻, is added. Because Ag₂CrO₄ is more soluble than AgCl, Ag₂CrO₄ precipitates out only after all the Cl⁻ ions have been precipitated as AgCl. Thus, when all Cl⁻ ions have reacted, Ag₂CrO₄ precipitation begins, marking the equivalence point with a rust-colored precipitate.
**Real-World Application in Food Chemistry**
As a food chemist for a major potato chip company, you are tasked with determining the salt content of new products for labeling. Potato chips are seasoned with table salt, NaCl. You weigh a handful of chips, boil them in water to extract salt, and filter the boiled chips to remove solid pieces. The chip filtrate is analyzed for Cl⁻ concentration using the Mohr method.
1. Prepare a silver nitrate solution, AgNO₃.
2. Titrate it against 0.500 g of KCl using the Mohr method. It takes 61.2 mL of AgNO₃ titrant to reach the equivalence point.
3. Use the same solution to analyze the chip filtrate in another Mohr reaction. A rusty brown precipitate forms when 46.2 mL of titrant is added.
**Part A**
If the chip sample used for the filtrate weighed 83.5 g, calculate the NaCl present in one serving (115 g) of chips. Express your answer to three significant figures with appropriate units. Enter the result in the provided field for "salt/serving."
- [Use the calculation feature to enter your answer]
This educational exercise demonstrates the practical application of the Mohr method in analytical chemistry for real-world food product analysis.
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