The flame change color because the electron is excited by heat and jump to a higher energy level to give out a specific frequency of light which gives out different colors depends on the compounds.
Measured 10 grams of NaCI2
dissolving NaCI2 in H2O
Fill the volumetric flask with salt water solution.
The equation for Molarity in for 10 g fo NaCI2 in 250ml of H2O