Methylene blue, from its aqueous solution, is adsorbed on activated charcoal at 25°C. For this process, the correct statement is (a) The adsorption requires activation at 25°C(b) The adsorption is accompanied by a decrease in enthalpy(c) The adsorption increases with increase of temperature(d) The adsorption is irreversible
Answers
the options b is the correct
Answer:
b) The adsorption is accompanied by a decrease in enthalpy is the correct answer.
Explanation:
Methylene blue has formula C16H18ClN3S.
It is also known as methylthioninium chloride.
It is a safe drug and is not toxic.
It is used in dyes and for other medicinal values.
Adsorption is adhesion of particles on its own surface.
Silica gel, metals are famous adsorbates.
Given that
Methylene blue, from its aqueous solution, is adsorbed on activated charcoal at 25°C.
To check the correct statement, we will see all the options.
(a) The adsorption requires activation at 25°C
It doesn't require activation at 25°C.
The statement is incorrect.
(b) The adsorption is accompanied by a decrease in enthalpy.
The process involved is physical adsorption.
It takes place only when there is exothermic reaction.
Exothermic reaction causes decrease in enthalpy.
Thus, this statement is correct
(c) The adsorption increases with increase of temperature.
Adsorption doesn't increase with increase in temperature.
The reaction is suitable at low temperature.
Thus the statement is incorrect.
(d) The adsorption is irreversible.
The adsorption process is reversible.
Thus statement is incorrect.