When you add CuSO4+KI the substance stays clear and when you add hexane to it it became brownish yellow and a red substance was present how do you explain this?
3 answers
I don't know what you mean when you say the solution was clear. You SHOULD mean that it has no ppt but you probably mean (because my students always confuse the words) colorless. However, if it is CuSO4 it should be blue. At any rate, what happens is the I^- reduces the Cu^+2 to Cu^+ and the I^- is oxidized to I2. Close observation should have noted a slight yellow color in the aqueous phase before the hexane was added; however, that happens only if the solution is concentrated enough to show the yellow color and the red ppt of CuI may have hidden the yellow color. When hexane is added, the I2 dissolve preferentially in the hexane and the I2/hexane layer turns color (to violet--or pink if the concn is low).
oh ok so why did it turn blue purple and pink when i added NH3 to it?
The Cu^+2 from the CuSO4 formed a complex ion that is deep blue to light blue, depending upon the concn, due to Cu(NH3)4^+2.