Answer is: a) in the presence of a base.
Phenolphthalein is colorless in acidic solutions and pink in basic solutions.
Acid-base indicators are usually weak acids or bases and they are chemical detectors for hydrogen or hydronium cations.
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄).
When solution turns phenolphthalein pink, it means it is basic (pH>7).
The answer to your question is,
An Arrhenius acid is a type of substance that separates in water to form Hydrogen ions.
-Mabel <3
Answer: For 1 mole of a single atom it is equal to its molar mass. And a single atom, 1 mole is equal to the Avogadro's Number.
Explanation: The relationship can be expressed through the following:
1 mole = molar mass of an atom/ compound
1 atom x 1 mole / 6.022x10^23 atoms
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