For 1 molal aqueous solution of the following compounds, which one will show the highest freezing point ?

Options

A. `[Co(H_(2)O)_(6)]Cl_(3)`
B. `[Co(H_(2)O)_(5)Cl]Cl_(2).H_(2)O`
C. `[Co(H_(2)O)_(4)Cl_(2)]Cl.2H_(2)O`
D. `[Co(H_(2)O)_(3)Cl_(3)]3H_(2)O`

Answer

D

Explanation

`[Co(H_(2)O_(6)]Cl_(3) hArr [Co(H_(2)O_(6)]^(3+) + 3Cl^(-)`(4 particles per mole)
`[Co(H_(2)O)_(5)]Cl_(2).H_(2)O hArr [Co(H_(2)O)_(5)Cl]^(2+) + 2Cl^(-)` (3 particles per mole)
`[Co(H_(2)O)_(5)Cl]Cl.2H_(2)O hArr [Co(H_(2)O_(4)Cl]^(2+) + Cl^(-1)` (2 particles per mole)
`[Co(H_(2)O)_(3)Cl_(3)].3H_(2)O hArr [Co(H_(2)O)_(2)Cl_(3)]` (1 particle per mole)