On treatment of 100 mL of 0.1 M solution of `COCl_(3).6H_(2)O` with excess of `AgNO_(3), 1.2 xx 10^(22)` ions are precipitated. The complex is

Options

A. `[Co(H_2 O)_4 Cl_2 ]Cl. 2H_2 O`
B. `[Co(H_2 O)_3 Cl_3 ] . 3H_2 O `
C. `[Co(H_2 O)_6] Cl_3`
D. `[Co(H_2 O)_5 Cl] Cl_2 .H_2 O`

Answer

D

Explanation

Moles of complex `=("Molarity" xx "Volume (mL)")/(1000)`
`=(100 xx 0.1)/(1000) = 0.1` mole
Moles of ions precipitated with excess of `AgNO_3`
`=(1.2xx10^(22))/(6.02xx10^(23))=0.02` moles
`=0.01 xx n = 0.02`
`therefore n=2`
It means `2Cl^(-)` ions present in ionization sphere
`therefore` Complex is `[Co(H_2 O)_5 Cl]Cl_2. H_2 O`