blank is used to dissipate the error brought about by impurities. What is the other reason of using blank in Mohr method?

Using the amount of chromate ion calculated to give the best end point gives such an intense yellow color that generally less than the optimum is used; therefore, generally, one must over titrate to get the end point color. The blank helps correct for that excess AgNO3 added to reach the end point. A second reason is that some people/students have trouble seeing the end point. In fact, through my years of teaching, I found that more students had more trouble with the Mohr method than any other procedure and all of it was because of the difficulty in seeing the end point. By using a blank, this problem corrects itself somewhat.

Well, using a blank in the Mohr method has two purposes. First, it helps dissipate the error caused by impurities. And second, it gives the analyst a chance to take a break and have a nice cup of tea. After all, analyzing chemicals can be stressful, so sometimes we all need a little "blank" time!

In the Mohr method, a blank is used to dissipate the error brought about by impurities and also to account for any residual color in the reagents or solution that may affect the accuracy of the measurement. Therefore, another reason for using a blank in the Mohr method is to establish a baseline color measurement and ensure that any color change observed is solely due to the presence of the analyte being measured. By subtracting the blank value from the sample measurements, a more accurate determination of the analyte concentration can be obtained.

In the Mohr method, a blank solution is used for two main reasons: to account for systematic errors and to establish a baseline for comparison.

1. Accounting for Systematic Errors: The presence of impurities or contaminants can introduce errors in the analysis. To compensate for these errors, a blank solution is used. It is typically a solution that contains all the reagents except the analyte of interest. By measuring the blank solution, any inherent impurities or contamination in the reagents can be determined and later subtracted from the measurements of the actual samples. This helps to achieve more accurate and precise results.

2. Establishing a Baseline: In the Mohr method, a blank solution is also used to establish a baseline or reference point for comparison. The blank solution does not contain any analyte, so it represents a zero concentration or absence of the analyte being measured. By measuring the blank solution and establishing it as a baseline, any colors or turbidity caused by impurities or other factors unrelated to the analyte can be accounted for and eliminated. This allows for more reliable and accurate determination of the analyte's concentration in the actual samples.

Overall, the use of a blank solution in the Mohr method helps to ensure more precise and accurate measurements while minimizing the impact of impurities and systematic errors.