Is there a reaction between CuSO4 + KI? When I performed the reaction, a brown and yellow color was formed but when I wrote out the molecular equation, I did not find a precipitate or gas evolution.
answered above.
The reaction between CuSO4 (copper(II) sulfate) and KI (potassium iodide) does result in a reaction. However, it does not yield a precipitate or gas evolution.
To understand why a brown and yellow color was formed, we need to consider the reaction products. When CuSO4 and KI are combined, they react to form CuI (copper(I) iodide) and K2SO4 (potassium sulfate). CuI is a yellow compound, and the brown color you observed may have been due to the presence of excess CuI.
The reaction can be represented by the following balanced chemical equation:
CuSO4 + 2KI -> CuI + K2SO4
It is important to note that some reactions may not produce a visible precipitate or gas. In this case, the change in color is the only observable evidence of the reaction taking place. It is also worth mentioning that the formation of a precipitate or gas evolution is not a requirement for indicating a chemical reaction.
In summary, although the reaction between CuSO4 and KI does not produce a precipitate or gas, it still results in a color change due to the formation of CuI, which gives a yellow color.