A portion of the test water with a volume of 25.0 ml was diluted with distilled water in a 500.0 ml volumetric flask and photometric in flame in the same way as standard solutions prepared from CaCl2. Photometry results are shown in the table:
option 1
CCa, mg / l 10.0 30.0 50.0 70.0 ???
Irel 16.0 47.6 80.2 111.0 76.9