273908
Primary valency of $\mathrm{Co}$ in $\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$ is
1 +1
2 +2
3 +3
4 +6
Explanation:
(C) : Werner's' stated that primary valency is satisfied by oxidation state. The compound is $\left[\mathrm{CO}(\mathrm{ex})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$ Let, $\mathrm{x}$ be the oxidation state of $\mathrm{Co}$ $\therefore \mathrm{X}+2(0)+2(-1)+(-1)=0$ or $\quad \mathrm{X}=+3$ Hence, the primary valency of the compound is +3 .
AMU-2017
COORDINATION COMPOUNDS
273910
On treatment of $100 \mathrm{~mL}$ of $0.1 \mathrm{M}$ solution of $\mathrm{CoCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}$ with excess of $\mathrm{AgNO}_{3} ; 1.2 \times 10^{22}$ ions are precipitated. The complex is
(D) : Given Volume of solution $=100 \mathrm{~mL}$ concentration of solution $=0.1 \mathrm{M}$ ions of $\mathrm{AgCl}=1.2 \times 10^{22}$ $\mathrm{COCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}+\mathrm{AgNO}_{3} \rightarrow \mathrm{AgCl} \downarrow+\left[\mathrm{COCl}_{\mathrm{x}} 6 \mathrm{H}_{2} \mathrm{O}\right]^{+}(\mathrm{ppt})$ $\therefore$ Number of moles of $\mathrm{CoCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}=$ Molarity $\times$ Volume $=0.1 \times \frac{100}{1000}$ $=0.01$ number of mole of $\mathrm{AgCl}=\frac{\text { Total ions of } \mathrm{AgCl}}{\text { Avogadro's number }}$ $\mathrm{n}_{\mathrm{AgCl}} =\frac{1.2 \times 10^{22}}{8.023 \times 10^{23}}$ $\mathrm{n}_{\mathrm{AgCl}} =0.02 \mathrm{~mol}$ $\because\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{\mathrm{z}} \mathrm{Cl}_{\mathrm{x}}\right] \mathrm{Cl}_{\mathrm{y}}$ $\therefore \mathrm{y} \times 0.01=0.02$ $\mathrm{y}=2$ Hence, the complex is $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right){ }_{5} \mathrm{Cl}_{1} \mathrm{Cl}_{2} \mathrm{H}_{2} \mathrm{O}\right.$
JEE Main-2017
COORDINATION COMPOUNDS
273922
Cobalt (III) chloride forms several octahedral complexes with ammonia. Which of the following will not give test for chloride ions with silver nitrate at $25^{\circ} \mathrm{C}$ ?
1 $\mathrm{CoCl}_{3} .5 \mathrm{NH}_{3}$
2 $\mathrm{CoCl}_{3} \cdot 6 \mathrm{NH}_{3}$
3 $\mathrm{CoCl}_{3} .3 \mathrm{NH}_{3}$
4 $\mathrm{CoCl}_{3} .4 \mathrm{NH}_{3}$
Explanation:
(C) : When no chloride ion present outside the coordination sphere then this complex will not given test with silver nitrate. $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl}_{2}+\mathrm{AgNO}_{3} \rightarrow 2 \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}+\mathrm{AgNO}_{3} \rightarrow 3 \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl}+\mathrm{AgNO}_{3} \rightarrow \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}+\mathrm{AgNO}_{3} \rightarrow \mathrm{No} \mathrm{AgCl}$ is formed Hence, $\mathrm{CoCl}_{3} 3 \mathrm{NH}_{3}$ will not give test for chloride ion with silver nitrate at $25^{\circ} \mathrm{C}$
NEET-2015
COORDINATION COMPOUNDS
273928
The correct formula of the complex tetraammine aqua chlorocobalt (III) chloride is
(D) : The correct formula of the given complex is tetraammine aqua chlorocobalt (III) chloride is $\left[\mathrm{CoCl}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$, because in it the oxidation number of $\mathrm{Co}$ is +3 . While in rest other options, oxidation number of $\mathrm{Co}$ is +2 $\left[\mathrm{CoCl}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$ $\Rightarrow \mathrm{x}+(-1)+0+(0 \times 4)+(-1) 2=0$ $\Rightarrow \mathrm{x}-3=0$ $\Rightarrow \mathrm{x}=+3$
273908
Primary valency of $\mathrm{Co}$ in $\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$ is
1 +1
2 +2
3 +3
4 +6
Explanation:
(C) : Werner's' stated that primary valency is satisfied by oxidation state. The compound is $\left[\mathrm{CO}(\mathrm{ex})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$ Let, $\mathrm{x}$ be the oxidation state of $\mathrm{Co}$ $\therefore \mathrm{X}+2(0)+2(-1)+(-1)=0$ or $\quad \mathrm{X}=+3$ Hence, the primary valency of the compound is +3 .
AMU-2017
COORDINATION COMPOUNDS
273910
On treatment of $100 \mathrm{~mL}$ of $0.1 \mathrm{M}$ solution of $\mathrm{CoCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}$ with excess of $\mathrm{AgNO}_{3} ; 1.2 \times 10^{22}$ ions are precipitated. The complex is
(D) : Given Volume of solution $=100 \mathrm{~mL}$ concentration of solution $=0.1 \mathrm{M}$ ions of $\mathrm{AgCl}=1.2 \times 10^{22}$ $\mathrm{COCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}+\mathrm{AgNO}_{3} \rightarrow \mathrm{AgCl} \downarrow+\left[\mathrm{COCl}_{\mathrm{x}} 6 \mathrm{H}_{2} \mathrm{O}\right]^{+}(\mathrm{ppt})$ $\therefore$ Number of moles of $\mathrm{CoCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}=$ Molarity $\times$ Volume $=0.1 \times \frac{100}{1000}$ $=0.01$ number of mole of $\mathrm{AgCl}=\frac{\text { Total ions of } \mathrm{AgCl}}{\text { Avogadro's number }}$ $\mathrm{n}_{\mathrm{AgCl}} =\frac{1.2 \times 10^{22}}{8.023 \times 10^{23}}$ $\mathrm{n}_{\mathrm{AgCl}} =0.02 \mathrm{~mol}$ $\because\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{\mathrm{z}} \mathrm{Cl}_{\mathrm{x}}\right] \mathrm{Cl}_{\mathrm{y}}$ $\therefore \mathrm{y} \times 0.01=0.02$ $\mathrm{y}=2$ Hence, the complex is $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right){ }_{5} \mathrm{Cl}_{1} \mathrm{Cl}_{2} \mathrm{H}_{2} \mathrm{O}\right.$
JEE Main-2017
COORDINATION COMPOUNDS
273922
Cobalt (III) chloride forms several octahedral complexes with ammonia. Which of the following will not give test for chloride ions with silver nitrate at $25^{\circ} \mathrm{C}$ ?
1 $\mathrm{CoCl}_{3} .5 \mathrm{NH}_{3}$
2 $\mathrm{CoCl}_{3} \cdot 6 \mathrm{NH}_{3}$
3 $\mathrm{CoCl}_{3} .3 \mathrm{NH}_{3}$
4 $\mathrm{CoCl}_{3} .4 \mathrm{NH}_{3}$
Explanation:
(C) : When no chloride ion present outside the coordination sphere then this complex will not given test with silver nitrate. $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl}_{2}+\mathrm{AgNO}_{3} \rightarrow 2 \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}+\mathrm{AgNO}_{3} \rightarrow 3 \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl}+\mathrm{AgNO}_{3} \rightarrow \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}+\mathrm{AgNO}_{3} \rightarrow \mathrm{No} \mathrm{AgCl}$ is formed Hence, $\mathrm{CoCl}_{3} 3 \mathrm{NH}_{3}$ will not give test for chloride ion with silver nitrate at $25^{\circ} \mathrm{C}$
NEET-2015
COORDINATION COMPOUNDS
273928
The correct formula of the complex tetraammine aqua chlorocobalt (III) chloride is
(D) : The correct formula of the given complex is tetraammine aqua chlorocobalt (III) chloride is $\left[\mathrm{CoCl}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$, because in it the oxidation number of $\mathrm{Co}$ is +3 . While in rest other options, oxidation number of $\mathrm{Co}$ is +2 $\left[\mathrm{CoCl}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$ $\Rightarrow \mathrm{x}+(-1)+0+(0 \times 4)+(-1) 2=0$ $\Rightarrow \mathrm{x}-3=0$ $\Rightarrow \mathrm{x}=+3$
273908
Primary valency of $\mathrm{Co}$ in $\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$ is
1 +1
2 +2
3 +3
4 +6
Explanation:
(C) : Werner's' stated that primary valency is satisfied by oxidation state. The compound is $\left[\mathrm{CO}(\mathrm{ex})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$ Let, $\mathrm{x}$ be the oxidation state of $\mathrm{Co}$ $\therefore \mathrm{X}+2(0)+2(-1)+(-1)=0$ or $\quad \mathrm{X}=+3$ Hence, the primary valency of the compound is +3 .
AMU-2017
COORDINATION COMPOUNDS
273910
On treatment of $100 \mathrm{~mL}$ of $0.1 \mathrm{M}$ solution of $\mathrm{CoCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}$ with excess of $\mathrm{AgNO}_{3} ; 1.2 \times 10^{22}$ ions are precipitated. The complex is
(D) : Given Volume of solution $=100 \mathrm{~mL}$ concentration of solution $=0.1 \mathrm{M}$ ions of $\mathrm{AgCl}=1.2 \times 10^{22}$ $\mathrm{COCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}+\mathrm{AgNO}_{3} \rightarrow \mathrm{AgCl} \downarrow+\left[\mathrm{COCl}_{\mathrm{x}} 6 \mathrm{H}_{2} \mathrm{O}\right]^{+}(\mathrm{ppt})$ $\therefore$ Number of moles of $\mathrm{CoCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}=$ Molarity $\times$ Volume $=0.1 \times \frac{100}{1000}$ $=0.01$ number of mole of $\mathrm{AgCl}=\frac{\text { Total ions of } \mathrm{AgCl}}{\text { Avogadro's number }}$ $\mathrm{n}_{\mathrm{AgCl}} =\frac{1.2 \times 10^{22}}{8.023 \times 10^{23}}$ $\mathrm{n}_{\mathrm{AgCl}} =0.02 \mathrm{~mol}$ $\because\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{\mathrm{z}} \mathrm{Cl}_{\mathrm{x}}\right] \mathrm{Cl}_{\mathrm{y}}$ $\therefore \mathrm{y} \times 0.01=0.02$ $\mathrm{y}=2$ Hence, the complex is $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right){ }_{5} \mathrm{Cl}_{1} \mathrm{Cl}_{2} \mathrm{H}_{2} \mathrm{O}\right.$
JEE Main-2017
COORDINATION COMPOUNDS
273922
Cobalt (III) chloride forms several octahedral complexes with ammonia. Which of the following will not give test for chloride ions with silver nitrate at $25^{\circ} \mathrm{C}$ ?
1 $\mathrm{CoCl}_{3} .5 \mathrm{NH}_{3}$
2 $\mathrm{CoCl}_{3} \cdot 6 \mathrm{NH}_{3}$
3 $\mathrm{CoCl}_{3} .3 \mathrm{NH}_{3}$
4 $\mathrm{CoCl}_{3} .4 \mathrm{NH}_{3}$
Explanation:
(C) : When no chloride ion present outside the coordination sphere then this complex will not given test with silver nitrate. $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl}_{2}+\mathrm{AgNO}_{3} \rightarrow 2 \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}+\mathrm{AgNO}_{3} \rightarrow 3 \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl}+\mathrm{AgNO}_{3} \rightarrow \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}+\mathrm{AgNO}_{3} \rightarrow \mathrm{No} \mathrm{AgCl}$ is formed Hence, $\mathrm{CoCl}_{3} 3 \mathrm{NH}_{3}$ will not give test for chloride ion with silver nitrate at $25^{\circ} \mathrm{C}$
NEET-2015
COORDINATION COMPOUNDS
273928
The correct formula of the complex tetraammine aqua chlorocobalt (III) chloride is
(D) : The correct formula of the given complex is tetraammine aqua chlorocobalt (III) chloride is $\left[\mathrm{CoCl}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$, because in it the oxidation number of $\mathrm{Co}$ is +3 . While in rest other options, oxidation number of $\mathrm{Co}$ is +2 $\left[\mathrm{CoCl}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$ $\Rightarrow \mathrm{x}+(-1)+0+(0 \times 4)+(-1) 2=0$ $\Rightarrow \mathrm{x}-3=0$ $\Rightarrow \mathrm{x}=+3$
273908
Primary valency of $\mathrm{Co}$ in $\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$ is
1 +1
2 +2
3 +3
4 +6
Explanation:
(C) : Werner's' stated that primary valency is satisfied by oxidation state. The compound is $\left[\mathrm{CO}(\mathrm{ex})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$ Let, $\mathrm{x}$ be the oxidation state of $\mathrm{Co}$ $\therefore \mathrm{X}+2(0)+2(-1)+(-1)=0$ or $\quad \mathrm{X}=+3$ Hence, the primary valency of the compound is +3 .
AMU-2017
COORDINATION COMPOUNDS
273910
On treatment of $100 \mathrm{~mL}$ of $0.1 \mathrm{M}$ solution of $\mathrm{CoCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}$ with excess of $\mathrm{AgNO}_{3} ; 1.2 \times 10^{22}$ ions are precipitated. The complex is
(D) : Given Volume of solution $=100 \mathrm{~mL}$ concentration of solution $=0.1 \mathrm{M}$ ions of $\mathrm{AgCl}=1.2 \times 10^{22}$ $\mathrm{COCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}+\mathrm{AgNO}_{3} \rightarrow \mathrm{AgCl} \downarrow+\left[\mathrm{COCl}_{\mathrm{x}} 6 \mathrm{H}_{2} \mathrm{O}\right]^{+}(\mathrm{ppt})$ $\therefore$ Number of moles of $\mathrm{CoCl}_{3} \cdot 6 \mathrm{H}_{2} \mathrm{O}=$ Molarity $\times$ Volume $=0.1 \times \frac{100}{1000}$ $=0.01$ number of mole of $\mathrm{AgCl}=\frac{\text { Total ions of } \mathrm{AgCl}}{\text { Avogadro's number }}$ $\mathrm{n}_{\mathrm{AgCl}} =\frac{1.2 \times 10^{22}}{8.023 \times 10^{23}}$ $\mathrm{n}_{\mathrm{AgCl}} =0.02 \mathrm{~mol}$ $\because\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{\mathrm{z}} \mathrm{Cl}_{\mathrm{x}}\right] \mathrm{Cl}_{\mathrm{y}}$ $\therefore \mathrm{y} \times 0.01=0.02$ $\mathrm{y}=2$ Hence, the complex is $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right){ }_{5} \mathrm{Cl}_{1} \mathrm{Cl}_{2} \mathrm{H}_{2} \mathrm{O}\right.$
JEE Main-2017
COORDINATION COMPOUNDS
273922
Cobalt (III) chloride forms several octahedral complexes with ammonia. Which of the following will not give test for chloride ions with silver nitrate at $25^{\circ} \mathrm{C}$ ?
1 $\mathrm{CoCl}_{3} .5 \mathrm{NH}_{3}$
2 $\mathrm{CoCl}_{3} \cdot 6 \mathrm{NH}_{3}$
3 $\mathrm{CoCl}_{3} .3 \mathrm{NH}_{3}$
4 $\mathrm{CoCl}_{3} .4 \mathrm{NH}_{3}$
Explanation:
(C) : When no chloride ion present outside the coordination sphere then this complex will not given test with silver nitrate. $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl}_{2}+\mathrm{AgNO}_{3} \rightarrow 2 \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}+\mathrm{AgNO}_{3} \rightarrow 3 \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl}+\mathrm{AgNO}_{3} \rightarrow \mathrm{AgCl}$ $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}+\mathrm{AgNO}_{3} \rightarrow \mathrm{No} \mathrm{AgCl}$ is formed Hence, $\mathrm{CoCl}_{3} 3 \mathrm{NH}_{3}$ will not give test for chloride ion with silver nitrate at $25^{\circ} \mathrm{C}$
NEET-2015
COORDINATION COMPOUNDS
273928
The correct formula of the complex tetraammine aqua chlorocobalt (III) chloride is
(D) : The correct formula of the given complex is tetraammine aqua chlorocobalt (III) chloride is $\left[\mathrm{CoCl}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$, because in it the oxidation number of $\mathrm{Co}$ is +3 . While in rest other options, oxidation number of $\mathrm{Co}$ is +2 $\left[\mathrm{CoCl}\left(\mathrm{H}_{2} \mathrm{O}\right)\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{2}$ $\Rightarrow \mathrm{x}+(-1)+0+(0 \times 4)+(-1) 2=0$ $\Rightarrow \mathrm{x}-3=0$ $\Rightarrow \mathrm{x}=+3$
