Question

The van't Hoff factor for a very dilute solution of $Fe_2(SO_4)_3$ is

• A. 9
• B. 5
• C. 24
• D. none of these

Answer 1

Answer: (B)

5

Answer 2

$Fe_2(SO_4)_3$ is very dilute solution ionises as ${Fe_2(SO_4)_3 <=> 2Fe^{3+} + 3SO^{2-}_4}$. $\therefore$ one formula unit of ferric sulphate gives 5 ions in solution. Hence, $i$ = 5.