CBSE Class 12 · 2010 · Delhi Compartment · SolutionsShort Answer

A decimolar solution of potassium ferrocyanide, K

_{4}

[Fe(CN)

_{6}

], is 50% dissociated at 300 K. Calculate the value of van't Hoff factor for potassium ferrocyanide.

Answer: i = 3

Solution

_{4}

[Fe(CN)

_{6}

]

\to

^{+}

+ [Fe(CN)

_{6}

]

^{4 -}

, so

n = 5

ions.
For degree of dissociation

α

i = 1 + (n - 1) α = 1 + 4 α

With

α = 0.5

i = 1 + 4 \times 0.5

i = 3

CBSE Class 12 Board · 2010 · Delhi Compartment · Subjective