[wmolina]

Hi! I'm trying to take a video recording experiment of chemical change. Baking soda is to be mixed in calcium chloride inside a ziplock bag. Then phenol red is added. The solution reacts by changing from red to yellow. I currently don't have any phenol red in my lab, haven't been able to update our inventory ever since the pandemic hit. Are there alternatives I can use for phenol red? I've tried phenolphthalein and I'm not getting any changes.

I should probably mention that I am not a chemist by profession, I'm a biologist and I admit this is quite a gray area for me despite how "easy" the experiment seems.

Hoping for any kind of advice. Thanks.

[billnotgatez]

There is a list here

pH indicator
https://en.wikipedia.org/wiki/PH_indicator

Naturally occurring pH indicators
https://en.wikipedia.org/wiki/PH_indicator#Naturally_occurring_pH_indicators

Red cabbage maybe

Let us know how you make out

[AWK]

What are you going to get from this experiment? The pH of the NaHCO₃ solution is about 8, the pH of the CaCl2 solution is 4-8 depending on the preparation method. Depending on the molar ratios you will get an intermediate pH. A white precipitate will form upon heating. Phenolphthalein will remain colorless, red cabbage juice will change color slightly.
Pour some NaHCO₃ solution into the test tube, add phenolphthalein and start heating. At temperatures over 50°C, the solution turns pink. This can be done in a glass of hot water. This reaction is irreversible.