Question

The blank solution used to calibrate the spectrophotometer is 10.0mL of 0.2M Fe(NO3)3 diluted to 25.0mL with 0.1M HNO3. Why is this solution preferred to simply using de-ionized water for the calibration?

Answer 1

This solution is preferred to using de-ionized water for the calibration because it provides a more accurate and reliable calibration. The Fe(NO3)3 solution provides a known concentration of a colored compound, which can be used to accurately measure the absorbance of the spectrophotometer. De-ionized water does not provide a known concentration of a colored compound, so it is not as reliable for calibrating the spectrophotometer.