135. Solving a chemistry problem

135. Solving a chemistry problem

12. During photometric titration on a single-beam photocolorimeter of 10 ml of a KMnO4 solution with a NaNO2 solution, the titer of which is 0.0015 g/ml, the following data were obtained:
Volume of NaNO2 solution, ml 0 0.5 1.0 1.25 1.5 1.75 2.0
Galvanometer readings 50 59.0 66.5 75.0 77.5 77.0 78.0
The deviation for the background was 80 divisions of the scale. Determine the normality of the test solution.

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