Question

Compound `PdCl_(4). 6H_(2)O` is a hydrated complex, 1 molal aqueous solution of it has freezing point 269.28 K. Assuming 100% ionization of complex, calculate the molecular formula of the complex (`K_(f)` for water = 1.86 K `mol^(-1)`)
A. `[Pd(H_(2)O)_(6)] Cl_(4)`
B. `[Pd (H_(2) O)_(4) Cl_(2)] Cl_(2).2H_(2)O`
C. `[Pd(H_(2)O)_(3) Cl_(3)] Cl. 3H_(2)O`
D. `[Pd(H_(2)O)_(2) Cl_(4)].4H_(2)O`

Answer 1

Correct Answer - C
`I = ("Normal molar mass")/("Observed molar mass")`
`= (164)/(65.6) = 2.5`
`alpha = (I - 1)/(n - 1) " n = 3` (number of ions)
`= (2.5 - 1)/(3 - 1) = (1.5)/(2) = 0.75`
`:.` Percentage ionization of `MX_(2)` will be 75%