DIFFERENCE BETWEEN ACID AND BASE AND CONCEPT OF PHENOPHTHALEIN

DIFFERENCE BETWEEN ACID AND BASE:

Sr. no.

Acid Base
1. They are sour in taste. They are bitter in taste.
2. They usually burn the skin. They slippery to touch.
3. Acids are those substances which turn blue litmus to red. Bases are those substances which turn red litmus to blue.
4. The effect of Phenolphthalein :

Acids show no reaction with Phenolphthalein so acids remain colorless.

The effect of Phenolphthalein :

Bases show reaction with Phenolphthalein so bases make it pink.

5. The PH of acids is less than 7 and could be 1 in the case of strong acids. The PH of acids is greater than 7 and could be 14 in the case of strong bases.
6. According to Arrhenius theory:

An acid is any chemical compound which when dissolved in water gives H+ ions (hydrogen ion) or H3O+ ion (Hydronium ion) in the solution.

According to Arrhenius theory:

A base is any chemical compound which when dissolved in water gives OH- ions (hydroxyl ion) in the solution.

7. According to Bronstead Theory:

An acid is a substance which donates a proton.

According to Bronstead Theory:

A base is a substance which accepts a proton.

8. According to Lewis theory, acids accept an electron pair. According to Lewis theory, bases donate an electron pair.
9. Example: HCl (Hydrochloric Acid), H2SO4 (Sulphuric Acid) Example: NaOH (Sodium Hydroxide), KOH  (Potassium Hydroxide)

Phenolphthalein:

It is a chemical compound with the formula C20H14O4. It is often used as an indicator in titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.

Phenolphthalein is insoluble in water and usually is dissolved in alcohols for use in experiments. It is a weak acid which can lose H+ ions in solution.

  • Important point to remember:

The Phenolphthalein molecule is colorless but Phenolphthalein ion is pink.

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