To determine the purity of a sample of Na2HPO4, a 2.469-g sample is dissolved and diluted to volume in a 100-mL volumetric flask. Analysis of the resulting solution gives an absorbance of 0.135. What is the purity of the Na2HPO4

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gbenewaeternity gbenewaeternity · Answer 1 · 2020-04-19T10:14:23+02:00

Question: The question is incomplete. below is the calibrated data of the question and the answer.

ppm Absorbance

2130 0.048

4260 0.110

6400 0.173

8530 0.230

Answer:

% purity = 95.32

Explanation:

NOW MOLAR MASS OF Na2HPO4 =141.96

ATOMIC MASS OF PHOSPOROUS=30.974

141.96/30.974 =4.583 g

If 4.583g of Na2HPO4 is added in 1000 ml volumetric flask and make the volume to 1L with water, you will get 1000 ppm P solution

Therefore, 2.469g in 100 mL =5387.300 PPM

Calculating the percentage error, we have

%ERROR=(5387.300-5146.118)/5146.118 *100

=4.68

SO %PURITY = 100-4.68 =95.32