Question

Methylene blue is adsorbed on activated charcoal at ${25}^{0}C$ from its aqueous solution. Which is the correct statement for this process?

• A. The adsorption requires activation at ${25}^{0}C$.
• B. The adsorption is accompanied by a decrease in enthalpy.
• C. The adsorption increases with increase of temperature.
• D. The adsorption is irreversible.

Answer 1

The correct option is B The adsorption is accompanied by a decrease in enthalpy.

Adsorption of methylene blue on activated charcoal is physical adsorption. Hence, it is characterised by decrease in enthalpy.