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MODEL PAPER 9 — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryMODEL PAPER 95 Marks
Question
Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration, and coordination number. Also, give stereochemistry and magnetic moment of the complex:
$a. \left.K \left[ Cr \left( H _2 O \right)_2\right\}\left( C _2 O _4\right)_2\right] \cdot 3 H _2 O$
$b. \left[ Co \left( NH _3\right)_5 Cl \right] Cl _2$
$c. CrCl _3( py )_3$
$d. Cs \left[ FeCl _4\right]$
$e. K _4\left[ Mn ( CN )_6\right]$
✓

Answer

$a. \left.K \left[ Cr \left( H _2 O \right)_2\right\}\left( C _2 O _4\right)_2\right] \cdot 3 H _2 O$ The $\text{IUPAC}$ name $=$ Potassium diaquadioxalatochromate $(III)$ trihydrate
The Oxidation state of chromium $=3$
Electronic configuration: $3 d^3: t_{2 g}{ }^3$
Coordination number od compound $=6$
Shape: octahedral
Stereochemistry:
Image
$\text { Magnetic moment, } \mu=\sqrt{n(n+2)}$
$=\sqrt{3(3+2)}$
$=\sqrt{15} \sim 3.87 B M$
$b. \left[ Co \left( NH _3\right)_5 Cl \right] Cl _2$ The $\text{IUPAC}$ name: Pentaamminechloridocobalt$(III)$ chloride
The oxidation state of $Co =+3$
Coordination number of compound $=6$
Shape: octahedral.
Electronic configuration:
$d^6: t_{2 g}{ }^6$
Stereochemistry:
Image
Magnetic Moment $=0$
$c. CrCl _3( py ) 3$ The $\text{IUPAC}$ name: Trichloridotripyridinechromium $(III)$
The oxidation state of chromium $=+3$
Electronic configuration for $d^3=t_{2 g}{ }^3$
Coordination number of compound $=6$
Shape: octahedral.
Stereochemistry:​​​​​​​
Image
Both isomers are optically active. Therefore, a total of $4$ isomers exist. Magnetic moment,
$\mu=\sqrt{n(n+2)}=\sqrt{3(3+2)}$
$=\sqrt{15} \sim 3.87 B M$
$d. Cs \left[ FeCl _4\right]$ The $\text{IUPAC}$ name : Caesium tetrachloroferrate $(III)$
The oxidation state of $Fe =+3$
Electronic configuration of $d^6=e_g{ }^2 t_{2 g}{ }^3$
Coordination number of compound $=4$
Shape: tetrahedral
Stereochemistry: optically inactive
Magnetic moment:
$\mu=\sqrt{n(n+2)}=\sqrt{5(5+2)}$
$=\sqrt{35} \sim 6 B M$
$e. K _4\left[ Mn ( CN )_6\right]$ The IUPAC name $=$ Potassium hexacyanomanganate $(II)$
The oxidation state of manganese $=+2$
Electronic configuration: $d^{5+}: t_{2 g}{ }^5$
Coordination number of compound $=6$ Shape: octahedral.
Stereochemistry: optically inactive Magnetic moment, $\mu=\sqrt{n(n+2)}$
$=\sqrt{1(1+2)}=\sqrt{3}$
$=1.732$

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