The correct order of the stoichiometries of `AgCl` formed when `AgNO_3` in excess is treated with the complexes: `CoCl_(3).6NH_3, CoCl_(3).5NH_3, CoCl_(3). 4NH_3` respectively is:

Options

A. 1 AgCl, 3 AgCl, 2 AgCl
B. 3 AgCl, 1 AgCl, 2 AgCl
C. 3 AgCl, 2 AgCl, 1 AgCl
D. 2 AgCl, 3 AgCl, 1 AgCl

Answer

C

Explanation

Remembering that coordination number of Co is 6, the complex `CoCl_(3).6NH_(3)` can be written as `[Co(NH_(3))_(6)]Cl_(3)` which provides `3 Cl^(-)` ions to be precipitated with excess of `AgNO_(3)` solution giving 3 moles of AgCl precipitate. Similarly, `CoCl_(3).5 NH_(3)` is `[Co(NH_(3))_(5)Cl]Cl_(2)` which gives 2 moles of AgCl precipitate and `CoCl_(2).4 NH_(3)` is `[Co(NH_(3))_(4)Cl_(2)]Cl` which gives 1 mole of AgCl precipitate with `AgNO_(3)` solution. Thus, the correct order of stoichiometries of AgCl formed is 3 AgCl, 2 AgCl and 1 AgCl.