Question

If $FeC{{l}_{3}}.{{H}_{2}}O$would exist as complex, one mole of it in aqueous solution on reaction with an excess of $AgN{{O}_{3}}$forms:
(A)- 1 mole of AgCl (white precipitate)
(B)- 2 moles of AgCl
(C)- 3 moles of AgCl
(D)- No reaction

Answer 1

Hint: Silver nitrate is an inorganic compound in which silver ions are three-coordinated in a trigonal planar arrangement. Other names of silver nitrate are nitric acid silver (+1) salt, Lapis infernalis, and Argentous nitrate. It is used as halide abstraction in many inorganic reactions.

Complete Step by step solution:
-The coordination complex $FeC{{l}_{3}}.{{H}_{2}}O$can be represented as- $[Fe{{({{H}_{2}}O)}_{4}}C{{l}_{2}}].Cl.{{H}_{2}}O$
-The coordination complex of iron has one chlorine atom present outside the ionization sphere, hence only one chlorine atom can ionize and react with the nitrate part of silver nitrate.
-The reaction of the iron complex with silver chloride is given as-
$[Fe{{({{H}_{2}}O)}_{4}}C{{l}_{2}}].Cl.{{H}_{2}}O+AgN{{O}_{3}}\to [Fe{{({{H}_{2}}O)}_{4}}C{{l}_{2}}]N{{O}_{3}}.2{{H}_{2}}O+AgCl$
-So, it is clear that only 1 mole of silver nitrate can give one mole of silver chloride which is a white precipitate formed in the reaction.

Therefore, the correct answer is option A.

Additional information:
-Coordination complexes are coordination complexes that consist of a central atom or ion, which is usually metallic and forms the coordination centre. The metal atom is further bonded to negatively charged molecules known as ligands or complexing agents.
-In coordination chemistry, the first coordination sphere represents the molecules that are tightly and directly bonded to the central metal atom. The interaction between the molecules and atoms of the first coordination sphere with the metal atom is usually hydrogen bonding.
-The second coordination sphere consists of ions(especially in charged complexes) or molecules (especially those that have hydrogen bonds to ligands in the first coordination sphere) and portions of a ligand backbone. The ions or molecules of the second coordination sphere has a less direct influence on the reactivity and chemical properties of the metal complex.

Note: The silver cation, $A{{g}^{+}}$reacts quickly with the halide atom to produce the insoluble silver halide, which is a precipitate. If the halide used is Bromide, then a cream precipitate is formed. If the halide is used as chloride, then white precipitate is formed. If the halide used is iodide, then yellow precipitate is formed.