Arrange the following complexes in increasing order of number of moles of silver chloride precipitated when one mole of each is reacted with excess of silver nitrate.

(A) $[Co(NH_3)_4Cl_2]Cl$
(B) $[Co(NH_3)_5Cl]Cl_2$
(C) $[Co(NH_3)_3Cl_3]$
(D) $[Co(NH_3)_6]Cl_3$

Choose the correct answer from the options given below:

(C), (A), (B), (D)

The correct answer is Option (1) → (C), (A), (B), (D)

To find the number of moles of AgCl precipitated, we count only the ionisable Cl⁻ ions outside the coordination sphere.

• (C) [Co(NH₃)₃Cl₃] → no Cl⁻ outside → 0 mol AgCl
• (A) [Co(NH₃)₄Cl₂]Cl → 1 Cl⁻ outside → 1 mol AgCl
• (B) [Co(NH₃)₅Cl]Cl₂ → 2 Cl⁻ outside → 2 mol AgCl
• (D) [Co(NH₃)₆]Cl₃ → 3 Cl⁻ outside → 3 mol AgCl