Question

Which solution contains phenolphthalein pink?

Answer 1

If hydrogen ions (H+, as found in an acid) were added to the pink solution, the equilibrium would switch, and the solution would be colorless. Adding hydroxide ions (OH-, as found in bases) will change the phenolphthalein into its ion and turn the solution pink.
Chemical formula: C20H14O4
Solubility in water: 400 mg/L
GHS precautionary statements: P201, P281, P308+313

Answer 2

Any liquid with a pH above 8.2.

Phenolphthalein is naturally colorless but turns pink in alkaline solutions. The compound remains colorless throughout the range of acidic pH levels but begins to turn pink at a pH level of 8.2 and continues to a bright magenta at pH 10 and above.