Question

Identify the approximate color you would expect if you were to test each household item using a cabbage pH indicator.


coffee, pH 5


baking soda solution, pH 9


bleach, pH 13 (strong base)


toothpaste, pH 8


milk, pH 6.8


battery acid, pH 1, (strong acid)

Answer 1

Short answer: using red cabbage (anthocyanin) indicator, you’d expect roughly:

- Coffee (pH 5): purple / purple-blue
- Baking soda solution (pH 9): yellow‑green / greenish‑yellow
- Bleach (pH 13, strong base): yellow to yellow‑brown (olive/yellowish)
- Toothpaste (pH 8): green (greenish‑blue to green)
- Milk (pH 6.8): blue to blue‑green (near neutral)
- Battery acid (pH 1, strong acid): red / magenta (bright pinkish red)

Note: exact shades depend on indicator concentration, lighting and solution concentration, so these are approximate.