Detecting Acids and Bases

Red cabbage water is an indicator of pH. Although it can't be used to determine exact pH, it can distinguish between acid (pH of 0 to 6), neutral (pH near 7), and base (pH of 8 to 14).

acid           neutral           base
Spectrum for Cabbage Water Indicator
0   1   2   3   4   5   6   7   8   9   10  11  12  13  14

In this activity:

  • If the indicator turns the solution red or pink, the solution is an acid.
  • A purple solution indicates that it is neutral, neither an acid nor a base.
  • If the indicator turns the solution blue or green, the solution is a base.

Mysterious Solutions

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