Question

Observe the following abbrevations $ \pi_{obs}= $ observed colligative property $ {{\pi }_{cal}}= $ theoretical colligative property assuming normal behaviour of solute. van't Hoff factor $ (i) $ is given by

• A. $ i=\pi _{obs} \times \pi_{cal} $
• B. $ i=\pi_{obs}+\pi_{cal} $
• C. $ i=\pi_{obs} - \pi_{cal} $
• D. $ i=\frac{\pi_{obs}}{\pi_{cal}} $

Answer 1

Answer: (D)

van't Hoff factor $(i)$ is given by
$i=\frac{\text { observed value of colligative property }}{\text { normal value of colligative property }}$
The normal value of colligative property is the theoretically calculated value assuming no association or dissociation.
$\therefore i=\frac{\pi_{o b s}}{\pi_{c a l}}$