Question

0.2 g of fine animal charcoal is mixed with a half litre of acetic acid (2 M) solution and shaken for 30 minutes ?
a.) Concentration remains the same
b.) Concentration increases
c.) Concentration of the solution decreases
d.) None of the above

Answer 1

Hint: The charcoal is a very good adsorbent. The crushing of charcoal increases its surface area. More is the surface area, more will be the solution adsorbed. The concentration is the amount of a substance present in its aqueous solution. If some amount of present substance gets escaped out of the solution, then its concentration decreases.

Complete Solution :
As we all know that the charcoal has the property to adsorb. It is a very good adsorbent and is used to adsorb a variety of molecules in aqueous form. When the charcoal is mixed with acetic acid solution and is then shaken for 30 minutes. The shaking provides energy and the acetic acid solution gets adsorbed in the charcoal. Thus, the amount of acetic acid gets lowered in the solution. So, the concentration of the solution decreases.
So, the correct answer is “Option B”.

Note: The fine charcoal means the charcoal has been crushed into a fine powder. The charcoal adsorbs the solution and not absorbs. There is a difference between the two. The absorption means the solution gets absorbed into the bulk of the material and in case of adsorption, The material gets absorbed on the surface only. So with crushing, the number of molecules of charcoal will increase and thus, its surface area also increases. So, the more adsorption occurs.