posted by Ellen on .
We did a flame testing lab today with the following metal ions:
Barium, Ba ^2+
Calcium, Ca ^2+
Copper, Cu ^2+
Potassium, K ^+1
Strontium, Sr ^2+
Lithium, Li ^+1
The question asks to explain the effect of the nitrate ion solution on the color emission. Please help me with this. Thank you so much!
Frankly, I think the nitrate ion has little to do with it other than helping the salt volatilize in the flame. Generally, chlorides or nitrates are used for the flame tests of these cations and its done because those salts volatilize a little easier than some of th others.
Thank you for helping me with this.
In this case the tests were done with solutions, so the significance of the nitrate ion is that the all nitrates are soluble in water. If you had used another ion say sulfate then the barium sulfate is only sparingly soluble in water.
You should have also tested nitric acid and shown that this does not give a colour to the flame.
I found this but wasn't sure how accurate is was: 4.) There is a major effect of the nitrate ion in solution on the color emission because the nitrate ion is the oxidizing agent in the compound without it you could not produce a spectrum so there would not be an emission of color.