Hey there! I'm happy to help!
Quantitative data are data that have to with quantities (numbers).
For example, how many inches tall is the plant, what is the pH level of this fluid, what is the temperature of the meat, etc.
Qualitative data are data that can be described or that have a specific quality (qualitative).
For example, are the flowers yellow or green, is the fluid bubbling, does the meat smell burnt, etc.
We see that a solution turning blue doesn't have to do with numbers, so it is not quantitative. It is qualitative because it has to do with the quality (in this case, color) of the solution and not a numerical statistic.
Have a wonderful day and keep on learning! :D