Application of Co-ordination compounds Questions in English

(C) $EDTA$ is used for the estimation of $Ca^{2+}$ and $Mg^{2+}$ ions.
$EDTA$ has four carboxyl groups and two amine groups that can act as electron pair donors or Lewis bases.
The ability of $EDTA$ to potentially donate its six lone pairs of electrons for the formation of coordinate covalent bonds to metal cations.
In alkaline conditions $(pH > 9)$,it forms stable complexes with the alkaline earth metal ions $Ca^{2+}$ and $Mg^{2+}$.
The $EDTA$ reagent can be used to measure the total quantity of dissolved $Ca^{2+}$ and $Mg^{2+}$ ions in a water sample.
Thus,the total hardness of a water sample can be estimated by titration with a standard solution of $EDTA$.

(B) When potassium ferrocyanide $K_4[Fe(CN)_6]$ reacts with concentrated $H_2SO_4$,carbon monoxide $(CO)$ is produced due to the dehydrating nature of concentrated $H_2SO_4$.
When it reacts with dilute $H_2SO_4$,hydrogen cyanide $(HCN)$ gas is evolved.
The chemical reaction is:
$2K_4[Fe(CN)_6] + 3H_2SO_4 \rightarrow K_2Fe[Fe(CN)_6] + 3K_2SO_4 + 6HCN \uparrow$

(C) $EDTA$ is a hexadentate ligand that forms stable water-soluble complexes with metal ions. In the treatment of lead poisoning,it is administered as the $Calcium$ $disodium$ salt of $EDTA$ $(CaNa_2EDTA)$. This is because if the free acid or other salts were used,they might deplete the body's essential calcium levels,leading to hypocalcemia. The $Ca^{2+}$ ions in the complex are exchanged for $Pb^{2+}$ ions in the body,forming a stable,water-soluble lead-$EDTA$ complex that is excreted through urine.

(B) Insulin is a protein hormone that contains $Zn^{2+}$ ions as a cofactor for its structural stability.
Haemoglobin is a respiratory pigment in red blood cells that contains $Fe$ $(Iron)$ as the central metal ion in its heme group.

(B) The process of blueprinting involves the use of light-sensitive iron salts.
Specifically,ferric ammonium oxalate or ferric oxalate,$Fe_2(C_2O_4)_3$,is used as the light-sensitive component.
When exposed to light,the $Fe^{3+}$ ions are reduced to $Fe^{2+}$ ions,which then react with potassium ferricyanide to form a deep blue pigment known as Prussian blue,$Fe_4[Fe(CN)_6]_3$.
Therefore,the iron salt used in blue prints is $Fe_2(C_2O_4)_3$.

(B) The reaction of $Ferric$ $Chloride$ $(FeCl_3)$ with potassium thiocyanate $(KSCN)$ produces a blood-red coloured complex,$Fe(SCN)_3$ (or $[Fe(SCN)(H_2O)_5]^{2+}$ in aqueous solution).
The chemical equation is: $FeCl_3 + 3KSCN \rightarrow Fe(SCN)_3 + 3KCl$.

(D) The reaction between $FeCl_3$ and $K_4[Fe(CN)_6]$ is as follows:
$4FeCl_3 + 3K_4[Fe(CN)_6] \rightarrow Fe_4[Fe(CN)_6]_3 + 12KCl$.
The product $Fe_4[Fe(CN)_6]_3$ is known as Prussian blue.

(D) The extraction of $Ag$ from its sulphide ore (argentite,$Ag_2S$) involves the formation of the dicyanoargentate$(I)$ complex,$[Ag(CN)_2]^-$.
The removal of unreacted silver bromide $(AgBr)$ from a photographic plate (fixing process) involves the formation of the thiosulphatoargentate$(I)$ complex,$[Ag(S_2O_3)_2]^{3-}$.
Therefore,the complexes involved are $[Ag(CN)_2]^-$ and $[Ag(S_2O_3)_2]^{3-}$ respectively.

(A) The correct matches are:
$(a)$ Chlorophyll contains Magnesium $(Mg)$ as the central metal atom. So,$a-(t)$.
$(b)$ Blood pigment (Hemoglobin) contains Iron $(Fe)$ as the central metal atom. So,$b-(s)$.
$(c)$ Wilkinson catalyst is $[RhCl(PPh_3)_3]$,which contains Rhodium $(Rh)$ as the central metal atom. So,$c-(p)$.
$(d)$ Vitamin $B_{12}$ (Cyanocobalamin) contains Cobalt $(Co)$ as the central metal atom. So,$d-(q)$.
Therefore,the correct sequence is $a-(t), b-(s), c-(p), d-(q)$.

(A) $cis-platin$,which is $cis-[Pt(NH_3)_2Cl_2]$,is a well-known chemotherapy medication used to treat a number of cancers. The $trans$ isomer is not effective as an anticancer agent.

(D) Sodium nitroprusside is $Na_2[Fe(CN)_5NO]$.
In this complex,the iron is in the $+2$ oxidation state,and the $NO$ ligand is present as $NO^{+}$.
It reacts with $S^{2-}$ ions to form a violet-colored complex,$Na_4[Fe(CN)_5(NOS)]$,which is used as a qualitative test for sulfide ions.
Therefore,all the given statements are correct.

(B) $1$. Mond's process is used for the purification of nickel,involving the formation of volatile nickel tetracarbonyl,$[Ni(CO)_4]$. This is correct.
$2$. $Ni^{+2}$ ions are estimated using $DMG$ (Dimethylglyoxime),not $EDTA$. $EDTA$ is typically used for the estimation of $Ca^{+2}$ and $Mg^{+2}$ ions in water hardness. Thus,this is the wrong match.
$3$. The red pigment of blood is hemoglobin,which contains $Fe^{+2}$ as the central metal ion. This is correct.
$4$. $Cis-[Pt(NH_3)_2Cl_2]$ (Cisplatin) is a well-known coordination compound used in cancer chemotherapy. This is correct.

(A) Initially,the ligand is consumed by the metal ion to form the complex $(C)$. Since neither the metal ion $(M)$ nor the complex $(C)$ absorbs light,the absorbance $(A)$ remains near zero or constant during this phase.
After the equivalence point is reached,all metal ions have been converted into the complex. Any further addition of the ligand $(L)$ increases its concentration in the solution.
Since the ligand $(L)$ absorbs light,the absorbance $(A)$ starts to increase linearly with the volume of the added ligand $(V)$.
Therefore,the plot shows a horizontal line followed by an upward slope,which corresponds to the graph in option $A$.

(A) In the electroplating of gold and silver,cyanide complexes are used to ensure a smooth and uniform deposition of the metal.
Specifically,the dicyanoaurate$(I)$ ion,$[Au(CN)_2]^-$,is used for gold plating.
Similarly,the dicyanoargentate$(I)$ ion,$[Ag(CN)_2]^-$,is used for silver plating.
Both are stable,soluble coordination complexes that provide a low concentration of free metal ions,which is essential for high-quality electroplating.

$(A)$ $Co$ is the central metal ion in Vitamin $B_{12}$.
$Zn$ is the central metal ion in the enzyme Carbonic anhydrase.
$Rh$ is the central metal in the Wilkinson catalyst, which is $[RhCl(PPh_3)_3]$.
$Mg$ is the central metal ion in Chlorophyll.
Therefore, the correct match is $a-iii, b-iv, c-i, d-ii$.

(D) $cis-[PtCl_2(NH_3)_2]$,commonly known as cisplatin,is used in chemotherapy to inhibit the growth of tumors.

(C) Ruby is a gemstone composed of aluminium oxide $(Al_2O_3)$ in which some $Al^{3+}$ ions are replaced by $Cr^{3+}$ ions in octahedral sites.
Statement $C$ is incorrect because ruby is a variety of corundum $(Al_2O_3)$,not beryl.
Beryl is the mineral associated with emeralds.
Therefore,the statement claiming $Cr^{3+}$ occupies sites in beryl is false.

(A) . $EDTA$ (ethylene diamine tetraacetate) is used for the treatment of lead poisoning.
$B$. $Cis-platin$ is used as an anti-cancer drug.
$C$. $D-penicillamine$ is used for copper poisoning.
$D$. $Desferrioxime \ B$ is used for iron poisoning.

(B) The coordination compound cis-diamminedichloroplatinum$(II)$,commonly known as cisplatin,is widely used as an anticancer drug.
Its chemical formula is $[Pt(NH_3)_2Cl_2]$.
The cis-isomer is effective in inhibiting the growth of tumors,whereas the trans-isomer is not.
Therefore,the correct option is $B$.

(D) Sodium nitroprusside is $Na_2[Fe(CN)_5NO]$. The metal cation present in it is $Fe^{2+}$ (iron).
Chlorophyll contains $Mg^{2+}$.
Vitamin $B_{12}$ contains $Co^{3+}$.
Cis-platin is $[Pt(NH_3)_2Cl_2]$,which contains $Pt^{2+}$.
Hemoglobin contains $Fe^{2+}$ as the central metal ion.
Therefore,the metal cation present in sodium nitroprusside $(Fe^{2+})$ is also present in hemoglobin.

(C) The reaction between copper$(II)$ ions and potassium ferrocyanide is a characteristic test for copper$(II)$ ions.
$2Cu^{2+} + [Fe(CN)_6]^{4-} \to Cu_2[Fe(CN)_6]$
This complex,$Cu_2[Fe(CN)_6]$,is known as copper$(II)$ hexacyanoferrate$(II)$,which forms a characteristic chocolate brown precipitate.

(A) The compound $[Cu(H_2O)_4]SO_4 \cdot H_2O$ (also written as $CuSO_4 \cdot 5H_2O$) contains the following types of bonds:
$1$. Electrovalent (ionic) bond: Between the $[Cu(H_2O)_4]^{2+}$ complex cation and the $SO_4^{2-}$ anion.
$2$. Covalent bond: Present within the $H_2O$ molecules and the $SO_4^{2-}$ polyatomic ion.
$3$. Coordinate covalent bond: Formed between the $Cu^{2+}$ central metal ion and the oxygen atoms of the four $H_2O$ ligands.
$4$. Hydrogen bond: Present between the fifth water molecule (lattice water) and the sulfate ions or the coordinated water molecules,as shown in the structure.

(A) $cis-[PtCl_2(NH_3)_2]$ is known as cisplatin.
Cisplatin is a chemotherapy medication used to treat several cancers,including testicular,ovarian,cervical,breast,bladder,head and neck,oesophageal,and lung cancers. It is administered via intravenous injection.

(B) $I$. In Mond's process,nickel reacts with carbon monoxide to form the volatile complex $Ni(CO)_4$.
$II$. In photography,unreacted $AgBr$ is removed by dissolving it in sodium thiosulfate $(Na_2S_2O_3)$ to form the soluble complex $[Ag(S_2O_3)_2]^{3-}$.
$III$. Lead poisoning is treated by using $EDTA$ (ethylenediaminetetraacetate),which forms a stable,water-soluble complex $[Pb(EDTA)]^{2-}$ that can be excreted from the body.

(B) The process of making blue prints,known as cyanotype,involves the use of iron salts.
Specifically,ferric ammonium oxalate or ferric oxalate,$Fe_2(C_2O_4)_3$,is used as the light-sensitive compound.
When exposed to light,the $Fe^{3+}$ ions are reduced to $Fe^{2+}$ ions,which then react with potassium ferricyanide to form a deep blue pigment called Prussian blue $(Fe_4[Fe(CN)_6]_3)$.

(B) When ferric chloride $(FeCl_3)$ reacts with potassium thiocyanate $(KSCN)$,it forms a blood-red colored complex known as ferric thiocyanate.
The chemical equation for this reaction is:
$Fe^{3+} (aq) + SCN^- (aq) \rightarrow [Fe(SCN)]^{2+} (aq)$
This complex,$[Fe(SCN)]^{2+}$,is responsible for the characteristic blood-red color.

(A) When $Cu^{2+}$ ions react with potassium ferrocyanide $(K_4[Fe(CN)_6])$,a reddish-brown precipitate of copper$(II)$ hexacyanoferrate$(II)$ is formed.
The chemical reaction is as follows:
$2Cu^{2+} + [Fe(CN)_6]^{4-} \rightarrow Cu_2[Fe(CN)_6]$
Thus,the formula of the reddish-brown precipitate is $Cu_2[Fe(CN)_6]$.

(C) In photography,sodium thiosulphate $(Na_2S_2O_3)$ is used as a 'fixing agent'.
After the development of the film,the unexposed silver bromide $(AgBr)$ remains on the film.
Sodium thiosulphate reacts with this unexposed $AgBr$ to form a soluble complex,sodium dithiosulphatoargentate$(I)$,which can be washed away.
The reaction is: $AgBr(s) + 2Na_2S_2O_3(aq) \rightarrow Na_3[Ag(S_2O_3)_2](aq) + NaBr(aq)$.

(B) $AgCl$ is a white precipitate that is insoluble in water but dissolves in excess of certain reagents due to the formation of soluble complex ions.
$(I)$ In excess $NH_{3(aq)}$,$AgCl$ forms the soluble complex $[Ag(NH_3)_2]Cl$.
$(II)$ In excess $Na_2S_2O_3$,$AgCl$ forms the soluble complex $Na_3[Ag(S_2O_3)_2]$.
$(III)$ In excess $NaCN$,$AgCl$ forms the soluble complex $Na[Ag(CN)_2]$.
Therefore,$AgCl$ dissolves in all three reagents.

(A) Chlorophyll is a green pigment found in plants that is essential for photosynthesis.
It is a coordination complex where the central metal ion is $Magnesium$ $(Mg^{2+})$,which is coordinated to a porphyrin ring system.
Therefore,chlorophyll is a $Magnesium$ complex.

(A) The reaction between potassium ferrocyanide $(K_4[Fe(CN)_6])$ and zinc sulfate $(ZnSO_4)$ results in the formation of a white precipitate of zinc ferrocyanide $(Zn_2[Fe(CN)_6])$.
Therefore,this is a precipitate formation reaction.

(A) The reaction between potassium ferrocyanide $(K_4[Fe(CN)_6])$ and copper sulfate $(CuSO_4)$ results in the formation of a chocolate-brown precipitate of copper ferrocyanide $(Cu_2[Fe(CN)_6])$.
Since a solid precipitate is formed as a product,this is classified as a precipitate formation reaction.
Therefore,the correct option is $A$.

(A) The reaction $NiCl_2 + 2dmg \xrightarrow{NH_4OH} Ni(dmg)_2 \downarrow$ involves the formation of a red-colored precipitate of nickel dimethylglyoximate $(Ni(dmg)_2)$.
Since the product $Ni(dmg)_2$ is indicated with a downward arrow $(\downarrow)$,it signifies the formation of a precipitate.
Therefore,the reaction is a precipitate formation reaction.

(C) The reaction is: $[Cr(NH_3)_6]^{3+} + 6HCl \longrightarrow Cr^{3+}(aq.) + 6NH_4Cl$.
In this reaction,the complex ion $[Cr(NH_3)_6]^{3+}$ is yellow/orange in color.
Upon reaction with $HCl$,it forms $Cr^{3+}(aq.)$ ions and $NH_4Cl$.
The $Cr^{3+}(aq.)$ ions in aqueous solution typically exhibit a violet or green color depending on the ligands,but the resulting solution is clear and colored.
However,in the context of qualitative analysis classification,this reaction results in a clear solution.
Therefore,it is classified as $C$ (For clear/colourless solution).

(A) The reaction between potassium ferricyanide $(K_3[Fe(CN)_6])$ and ferric chloride $(FeCl_3)$ results in the formation of ferric ferricyanide,which is $Fe[Fe(CN)_6]$.
This compound is known as Prussian blue or Turnbull's blue,which appears as a dark blue precipitate.
Since the product is a precipitate,it corresponds to the category of coloured precipitate.
Therefore,the correct assignment is $A$.

(A) The reaction between potassium ferricyanide $(K_3[Fe(CN)_6])$ and ferrous chloride $(FeCl_2)$ results in the formation of ferrous ferricyanide $(Fe_3[Fe(CN)_6]_2)$,which is commonly known as Turnbull's blue.
This compound appears as a deep blue coloured precipitate.
Therefore,the correct classification for this reaction is for a coloured precipitate.

(D) The reaction $Fe^{2+} + [Fe(CN)_6]^{4-} \to$ produces a white precipitate of $K_2Fe[Fe(CN)_6]$ (in the presence of $K^+$ ions),not a red-brown colouration. Therefore,option $D$ is the incorrect match.

(D) The reaction $K_4[Fe(CN)_6] + M^{x+}(aq.) \to M_4[Fe(CN)_6]_x \downarrow$ represents the formation of insoluble metal hexacyanoferrate$(II)$ precipitates.
$Cu^{2+}(aq.)$ reacts to form $Cu_2[Fe(CN)_6]$ (chocolate brown precipitate).
$Fe^{3+}(aq.)$ reacts to form $Fe_4[Fe(CN)_6]_3$ (Prussian blue precipitate).
$Zn^{2+}(aq.)$ reacts to form $Zn_2[Fe(CN)_6]$ (white precipitate).
Since all the given cations form precipitates with the hexacyanoferrate$(II)$ ion,none of them fail to respond to the reaction.

(B) Cis-platin,with the chemical formula $[Pt(NH_3)_2Cl_2]$,is a well-known chemotherapy medication used to treat various types of cancers,including testicular,ovarian,and bladder cancer. It works by binding to $DNA$ and interfering with cell division.

(C) In $CuSO_4 \cdot 5H_2O$:
$1$. Ionic bonds are present between $Cu^{2+}$ and $SO_4^{2-}$ ions.
$2$. Covalent bonds are present within the $SO_4^{2-}$ ion (between $S$ and $O$ atoms) and within the $H_2O$ molecules.
$3$. Coordinate covalent bonds are present between the $Cu^{2+}$ ion and the oxygen atom of the water molecule (as $Cu^{2+}$ acts as a Lewis acid and $H_2O$ acts as a ligand).

(A) The complex $[Co(NH_3)_5Br]SO_4$ dissociates in aqueous solution as $[Co(NH_3)_5Br]SO_4 \rightarrow [Co(NH_3)_5Br]^{2+} + SO_4^{2-}$.
When $BaCl_2$ or $Pb(NO_3)_2$ is added,the $SO_4^{2-}$ ions react to form a white precipitate of $BaSO_4$ or $PbSO_4$.
Among the given options,$PbCl_2$ is not a suitable reagent for testing sulfate ions as it is sparingly soluble. However,if we consider the reaction of $SO_4^{2-}$ with $Pb^{2+}$ ions,$PbSO_4$ is a white precipitate.
Since $PbCl_2$ is often used as a source of $Pb^{2+}$ ions in specific contexts,it is the most appropriate choice among the provided options to yield a white precipitate of $PbSO_4$.

(D) When potassium ferrocyanide $(K_4[Fe(CN)_6])$ is added to a ferric salt (e.g.,$FeCl_3$),it reacts to form ferric ferrocyanide,commonly known as Prussian blue.
The chemical reaction is: $4Fe^{3+} + 3[Fe(CN)_6]^{4-} \rightarrow Fe_4[Fe(CN)_6]_3$.
This complex,$Fe_4[Fe(CN)_6]_3$,is responsible for the intense blue color.

(B) The compound $cis-[PtCl_2(NH_3)_2]$,commonly known as cisplatin,is widely used as an effective anti-cancer drug in chemotherapy to treat various types of cancers.

(B) $Co^{2+}$ is the central metal ion in Vitamin $B_{12}$.
$Mg^{2+}$ is the central metal ion in chlorophyll,which is essential for photosynthesis.
$Fe^{2+}$ is the central metal ion in hemoglobin,responsible for oxygen transport.
$Se^{2+}$ is not a central metal ion in the Krebs cycle; the Krebs cycle involves various enzymes and cofactors,but selenium is not a primary coordination center in this context. Therefore,the pair $Se^{2+} - \text{Krebs cycle}$ is incorrect.

(A) The chemical formula for $cis$-platin is $[PtCl_2(NH_3)_2]$.
In this coordination complex,the central metal ion is $Pt^{2+}$.
The ligands attached to the central metal ion are ammonia $(NH_3)$ and chloride ions $(Cl^-)$.

(C) Chlorophyll is a green pigment found in plants that plays a crucial role in photosynthesis. It contains a porphyrin ring with a central magnesium $(Mg^{2+})$ ion,not calcium $(Ca^{2+})$. Therefore,the statement that chlorophyll contains calcium is incorrect.

(A) $AgCl$ is a sparingly soluble salt in water.
When $NH_4OH$ is added,it reacts with $AgCl$ to form a soluble coordination complex,diamminesilver$(I)$ chloride,which causes the precipitate to dissolve.
The chemical reaction is: $AgCl(s) + 2NH_4OH(aq) \to [Ag(NH_3)_2]Cl(aq) + 2H_2O(l)$.
Thus,both the Assertion and the Reason are correct,and the Reason is the correct explanation for the Assertion.