During the first week of June hols, I went to school but the lab was closed, however, I managed to borrow universal indicator liquid from the lab.
Together with Chin Ying, my partner, I went to buy vinegar, baking soda and distilled water. At her house, we tested out the pH of these substances using the indicator. I realised that vinegar and baking soda are rather weak acid and alkaline and cannot be used to recreate the pH scale. I also tried different types of soaps and detergents, as well as bleach. While detergent could reach a high pH of 11, I need a transparent liquid as any colour in the liquid may affect the pigments in the vegetables. Surprisingly, soaps and bleach were acidic! (About pH 4) Really puzzling. Perhaps the bleach was “fake bleach”.
Back at home, I continued to test two more types of bleach. One was an alkaline, pH 9 (quite weak and like baking soda), the other once again acidic.
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