E115. When constructing the calibration graph for the d

E115. When constructing the calibration graph for the d

E115. When constructing the calibration graph for the determination of nickel, a 10-4 M solution of nickel salt was used, an aliquot of which was diluted with ammonia-ammonia buffer to 25 ml and polygraphed, and the following data were obtained:
V, ml 1 2 3 4 5 6
h, mm 9 16 26.5 35 41 54
An alloy mass of 0.25 g containing nickel was dissolved in 50 ml of an acid mixture, 5 ml of the resulting solution was taken and diluted with the same buffer solution to 25 ml.
By polarography, a wave height of 22.7 mm was obtained.
What is the mass fraction of nickel in the alloy?

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