Question

Which one of the following is not explained by adsorption?

• A. When acetic acid solution is shaken with charcoal, the concentration of the acid decreases
• B. The white precipitate of $Mg(OH)_2$ attains blue colour when precipitated in the presence of magneson reagent
• C. The air becomes dry in the presence of silica gel
• D. An aqueous solution of NaOH attains pink colour with a drop of phenolphthalein

Answer 1

Answer: (D)

An aqueous solution of NaOH attains pink colour with a drop of phenolphthalein

Answer 2

Colour of the indicator changes due to change in pH and not because of adsorption