Question

Why is ammonia added to copper sulphate solution in colorimetric estimation?

Answer 1

Answer:

When ammonia is being added to the solution of copper sulphate for colorimetric estimation,an intense blue color of the cupric ammonia complex is formed, which is measured for absorbance for estimating the copper ions present in it.

Colorimetric estimation is the process of estimation of ions present in any coloured solution and hence ammonia is added to bring about the formation of the coloured complex.