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.
$\therefore i=\frac{{\pi }_{obs}}{{\pi }_{cal}}$