Answer:
Chemists use the Universal Indicator to identity acids and bases, as follows:
Strong acids: Red: 1, 2, 3.
Weak acids: Orange: 4, 5.
Neutral acids: Yellow, 6, 7. Green: 8. Blue: 9, 10. (blue is already weak base.
Weak base: Purple: 11, 12, 13, 14. (Last two are Strong base).