Question

For a very dilute solution of $H_3{PO}_3$, Van’t Hoff factor is:

• A. $i=7$
• B. $i=3$
• C. $i=4$
• D. $i=5$

Answer 1

Answer: (B)

$i=3$

Dissociation of $H_{3}P{O}_3$ is as follows:

$H_{3}P{O}_3$ $\to$ $2H^{+}+HP{O}_3^{-2}$

It produces 3 ions on dissociation. Hence, Van't Hoff factor = 3.