In this video, universal indicator is added to a solution of weakly concentrated sodium hydroxide (NaOH). This turns the solution purple. A 5% acetic acid solution is then added (in the form of commercially available cooking white vinegar) and the solution containing universal indicator then turns red.

The video supports the Europlanet Mars Collection of Educational Resources - 7. pH of Mars. https://www.europlanet-society.org/mars-collection-of-educational-resources-7-ph-of-mars/

Europlanet 2024 RI has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149.