Question

​Describe any two chemical reactions associated with change in colour of the compound??

Answer 1

When NaOH  solution is added with a drop of phenolphthalein solution, initially both having colorless but the reaction end with a pink color solution.
Another example, now take that same pink color and add few drop of HCl, after adding, we will find that the pink color disappeared and become colorless.
So, these are the example of chemical reaction associated with change in color of the compound.