Hermes2020
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I steamed some red cabbage in a stainless steel saucepan. When I drained off the water, I saw that it was an intense dark purple-blue.
I filtered the water through a coffee filter paper and tried adding some chemicals I had in the kitchen. I found that the cabbage pigment behaved like a pH indicator, as shown in the next photo. I had to dilute the solutions to show the colours more clearly.
The first glass on the left is the filtered water from the saucepan. It turned yellow-green after addition of some sodium hydroxide, which raised the pH to above 7. This is in the second glass. The third lovely blue colour is obtained at a pH lower than the second, but still above 7, by adding some sodium bicarbonate to the original water from the saucepan. The last, beautiful red solution, is after taking the pH below 7 by adding some vinegar.
I filtered the water through a coffee filter paper and tried adding some chemicals I had in the kitchen. I found that the cabbage pigment behaved like a pH indicator, as shown in the next photo. I had to dilute the solutions to show the colours more clearly.
The first glass on the left is the filtered water from the saucepan. It turned yellow-green after addition of some sodium hydroxide, which raised the pH to above 7. This is in the second glass. The third lovely blue colour is obtained at a pH lower than the second, but still above 7, by adding some sodium bicarbonate to the original water from the saucepan. The last, beautiful red solution, is after taking the pH below 7 by adding some vinegar.
