[suresh95]

Hi,
 This is a Lab work , when NaCl is added to CuSo₄, the blue color of CuSo₄ turned colorless. Does it indicate a chemical reaction has occurred or it is just a color change. There isn't a different color formed.
 Another question NH3 is added to FeCl₃, NH₃ to CuSo₄ The Color changes to Brown and a ring is formed , is there a precipitate (Precipitate settles to the bottom of the test tube).
thanks

[skyjumper]

wouldnt any color change indicate a chemical reaction?

Google is my hero

[zeoblade]

Have you figured out why the colour changes from bright blue?

When I did this reaction the solution changed from bright blue to a slight green tinge and then back to bright blue after adding excess water

I'm thinking there is some CuCl₂ that changes the colour

When I use KBr, the solution became bright green and returned to bright blue after excess water addition

I have a feeling there is a co-ordination complex of Cu(II) occurring but I can't be sure

Why would there be a strong reaction with KBr but give a slight green tinge with NaCl?

I thought the complex CuCl₄^2- is the reason because it is yellow and with blue would give green?