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).
This is the symbols for protons, neutrons, and electrons
Answer:
Brackett Series (n = 4)
Explanation:
The least energetic line of Hydrogen atom lies in <em>Brackett Series </em>when n = 4 because these are least energetic, have longer wavelengths and lies in Infrared region of spectrum. No traces of <em>Pfund series </em>are formed by H=atoms.
There is no reaction because of the common ion effect(which in this case is K)if there were a reaction the products would be the same as the reactants so no reaction happens