How Does Phenolphthalein React with Acids and Bases?
Phenolphthalein is an indicator of acids (colorless) and bases (pink). Sodium hydroxide is a base, and it was in the pitcher at the beginning, so when added to the phenolphthalein in beakers 2 and 4, it turned pink (top half of the graphic). The equilibrium shifts right, HIn decreases, and In- increases.

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Also, how does phenolphthalein change with acids and bases?

Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. When a base is added to the phenolphthalein, the equilibrium shifts, leading to more ionization as H+ ions are removed.

One may also ask, why does phenolphthalein turn pink in a base? Phenolphthalein (HIn) is weakly acidic in nature. And in aqueous solution, it dissociates into and ions. The pink colour of the solution is due to the concentration of ions in the solution. Under acidic conditions, the concentration of in the solution is very low and concentration of is high, hence it is colourless.

Then, is phenolphthalein an acid or base?

Phenolphthalein. Phenolphthalein is an organic compound (C20H14O4) used as an acid-base indicator. The compound is colorless in acidic solution and pinkish in basic solution (with the transition occuring around pH 9).

Is NaOH an acid or base?

NaOH is a base because when dissolved in water it dissociates into Na+ and OH- ions. It is the OH- (hydroxyl ion) which makes NaOH a base. In classical term a base is defined as a compound which reacts with an acid to form salt and water as depicted by the following equation. NaOH+HCl=NaCl+H2O.

Related Question Answers

Is HCl a strong acid?

A strong acid is an acid which is completely ionized in an aqueous solution. Hydrogen chloride (HCl) ionizes completely into hydrogen ions and chloride ions in water. A weak acid is an acid that ionizes only slightly in an aqueous solution. Because HCl is a strong acid, its conjugate base (Cl−) is extremely weak.

Is NaOH a strong base?

Sodium hydroxide (NaOH) is strong base because it fully dissociates in water to produce hydroxide ions. While ammonia (NH3) is weak base because it accepts protons from water to produce fewer hydroxide ions in solution. While weak bases produce fewer hydroxide ions, making the solution less basic.
Maya Lin-Takahashi

Maya Lin-Takahashi

Consumer Tech & Gadget Reviewer

Maya is a hardware enthusiast who tests and reviews smart home devices, smartphones, wearables, and audio gear. She focuses on practical consumer value and build quality.