The correct order of the stoichiometries of AgCl formed when AgNO3 in excess is treated with the complexes : CoCl3 6NH3, CoCl3 5NH3, CoCl3 4NH3 respectively is
- 3AgCl, 1AgCl, 2AgCl
- 3AgCl, 2AgCl, 1AgCl
- 2AgCl, 3AgCl, 2AgCl
- 1AgCl, 3AgCl, 2AgCl
Answer
(2) 3AgCl, 2AgCl, 1AgCl
Solution
Co(III) has coordination number 6; only the ionisable chloride ions (outside the coordination sphere) are precipitated as AgCl.
CoCl3 6NH3 = [Co(NH3)6]Cl3 ⇒ 3 AgCl
CoCl3 5NH3 = [Co(NH3)5Cl]Cl2 ⇒ 2 AgCl
CoCl3 4NH3 = [Co(NH3)4Cl2]Cl ⇒ 1 AgCl
As per NCERT (Werner's experiments), these complexes give 3, 2 and 1 mol of AgCl respectively.
Answer: (2)