Question

We explored the copper cycle. In the first step, copper was oxidized by nitric acid to make a green solution. Water was then added to the solution and the color changed from green to blue. Is this result supported by the spectrochemical series?

Answer 1

Answer:

Yes, the reaction is supported by spectrochemical series.

Explanation:

When copper oxidizes with concentrated nitric acid, it produces copper ions; and the nitric acid is then reduced to nitrogen dioxide, a very poisonous gas which is brown in color and with an irritating odor.

$Cu + 4HNO_{3} \rightarrow Cu(NO_{3})_{2} + 2NO_2+2H_2O$

The copper ions ($Cu^{2+}$) product which is initially coordinated to form nitrate ions from nitric acid and thus first gives the solution a green color.

Now when the solution is further diluted with water, the water molecules then displaces the nitrate ions  around the copper ions and causes the solution to change its color to blue. The reaction is -

$3Cu + 8HNO_3 \rightarrow 3Cu(NO_3)_2+ 2NO + 4H_2O$

Yes, the results are supported by spectrochemical series.