* Formation of a solid precipitate: The most obvious sign is the appearance of a solid, cloudy substance at the bottom of the test tube. This solid is the insoluble salt, which has come out of solution and formed a precipitate.
* Change in solution clarity: The solution will become less clear or even opaque as the insoluble salt forms and blocks the passage of light.
* Color change: Depending on the salt formed, the solution might change color. Some insoluble salts are brightly colored and will noticeably change the appearance of the solution.
* Possible settling: If the reaction is allowed to stand, the precipitate will often settle to the bottom of the test tube, leaving a clearer liquid layer above.
In summary, the formation of an insoluble salt will lead to the appearance of a solid precipitate, a decrease in solution clarity, and possibly a color change.
