Sodium Thiosulfate mixed with Potassium Iodide. These are two transparent liquids. When they are mixed, they create a different color of liquid, which is the chemical reaction.
Both the liquids should be clear, but because of the fact that we had to see the difference between the two chemicals, we set the Sodium Thiosulfate to be white, and the Potassium Iodide to grey.
Iodine Clock Reaction Chemical Experiment! [Motion picture]. (2014). America.
from
(https://www.youtube.com/watch?v=OPTdAmSx4m4)
Written Chemical Equation:
2Na(2)S(2)O(3) + KI ------> 2NaKI + Na(2)S(4)O(6)
It is single replacement.