274411
A metal $X$ on heating in nitrogen gas gives $Y . Y$ on treatment with $\mathrm{H}_{2} \mathrm{O}$ gives a colourless gas which when passed through $\mathrm{CuSO}_{4}$ solution gives a blue colour. $Y$ is
1 $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}$
2 $\mathrm{Mg}_{3} \mathrm{~N}_{2}$
3 $\mathrm{NH}_{3}$
4 $\mathrm{MgO}$
Explanation:
(B) : When magnesium metal is heated in nitrogen, it forms magnesium nitride. $3 \mathrm{Mg}+\mathrm{N}_{2} \rightarrow \mathrm{Mg}_{3} \mathrm{~N}_{2}$ Hydrolysis of magnesium nitride gives magnesium hydroxide and ammonia. $\mathrm{CuSO}_{4}+4 \mathrm{NH}_{3} \rightarrow\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{SO}_{4}$ $\mathrm{Mg}_{3} \mathrm{~N}_{2} \stackrel{\text { Water }}{\longrightarrow} \mathrm{Mg}(\mathrm{OH})_{2}+\mathrm{NH}_{3}$ When ammonia gas is dissolved in the copper sulphate solution blue colour is obtained.
Assam CEE-2014
COORDINATION COMPOUNDS
274412
The octahedral complex of a metal ion $\mathbf{M}^{3+}$ with four monodentate ligands $L_{1}, L_{2}, L_{3}$ and $L_{4}$ absorb wavelengths in the region of red, green, yellow and blue, respectively. The inreasing order of ligand strength of the four ligands is
(B) : $\begin{array}{lcccc}\text { Ligand : } \mathrm{L}_{1} \mathrm{~L}_{2} \mathrm{~L}_{3} \mathrm{~L}_{4} \\ \lambda_{\text {abs }} \text { Red } \text { Green } \text { Yellow } \text { Blue }\end{array}$ The order of Wavelength of absorption is Blue $<$ Green $<$ Yellow $<$ Red The order of splitting energy levels - $\mathrm{L}_{4}>\mathrm{L}_{2}>\mathrm{L}_{3}>\mathrm{L}_{1}$ Increasing order of ligand strength is - $\mathrm{L}_{1}<\mathrm{L}_{3}<\mathrm{L}_{2}<\mathrm{L}_{4}$
JEE Main 2014
COORDINATION COMPOUNDS
274414
Out of $\mathrm{TiF}_{6}^{2-}, \mathrm{CoF}_{6}^{3-}, \mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2-}(\mathrm{Z}$ of $\mathrm{Ti}=22, \mathrm{Co}=27, \mathrm{Cu}=29, \mathrm{Ni}=28)$ the colourless species are
1 $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2}$
2 $\mathrm{TiF}_{2}^{2-}$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$
3 $\mathrm{CoF}_{6}{ }^{3-}$ and $\mathrm{NiCl}_{4}{ }^{2-}$
4 $\mathrm{TiF}_{6}{ }^{2-}$ and $\mathrm{CoF}_{6}{ }^{3-}$
Explanation:
(B) : A species is coloured when it contain unpaired d-electron which are capable of undergoingd-d transition on absorption of light of a particular wavelength. In $\quad \mathrm{TiF}_{6}{ }^{2-} \quad \mathrm{Ti}^{4+}: 3 \mathrm{~d}^{0}$ colourless $\mathrm{CoF}_{6}{ }^{3-} \mathrm{Co}^{3+}: 3 \mathrm{~d}^{6}$ coloured $\mathrm{Cu}_{2} \mathrm{Cl}_{2} \quad \mathrm{Cu}^{+}: 3 \mathrm{~d}^{10}$ coloured $\mathrm{NiCl}_{4}^{2-} \quad \mathrm{Ni}^{2+}: 3 \mathrm{~d}^{8}$ colourless $\mathrm{TiF}_{6}{ }^{2-}\left(3 \mathrm{~d}^{0}\right)$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}\left(3 \mathrm{~d}^{10}\right)$ with empty and fully filled d-orbitals appear colourless as they are not capable by undergoing d-d transition.
AIPMT -2009
COORDINATION COMPOUNDS
274415
Which of the following complex ions is expected to absorb visible light?
1 $\left[\mathrm{Ti}(\text { en })_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]^{4+}$
(B) : Since $\mathrm{Cr}^{3+}$ in the complex has unpaired electrons in the d-orbital hence will be coloured. $\mathrm{Ti}=[\mathrm{Ar}] 3 \mathrm{~d}^{2} 4 \mathrm{~s}^{2}: \mathrm{Ti}^{4+}=3 \mathrm{~d}^{0}$ $\mathrm{Cr}=[\mathrm{Ar}] 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1} ; \mathrm{Cr}^{3+}=3 \mathrm{~d}^{3}$ $\mathrm{Zn}=[\mathrm{Ar}] 3 \mathrm{~d}^{10} 4 \mathrm{~s}^{2} ; \mathrm{Zn}^{2+}=3 \mathrm{~d}^{10}$ $\mathrm{Sc}=[\mathrm{Ar}] 3 \mathrm{~d}^{1} 4 \mathrm{~s}^{2} ; \mathrm{Sc}^{3+}=3 \mathrm{~d}^{0}$
AIPMT -2009
COORDINATION COMPOUNDS
274417
In which of the following pairs are both the ions coloured in aqueous solution? (At. no. : $\mathrm{Sc}=21, \mathrm{Ti}=22, \mathrm{Ni}=28, \mathrm{Cu}=29, \mathrm{Co}$ $=27$ )
274411
A metal $X$ on heating in nitrogen gas gives $Y . Y$ on treatment with $\mathrm{H}_{2} \mathrm{O}$ gives a colourless gas which when passed through $\mathrm{CuSO}_{4}$ solution gives a blue colour. $Y$ is
1 $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}$
2 $\mathrm{Mg}_{3} \mathrm{~N}_{2}$
3 $\mathrm{NH}_{3}$
4 $\mathrm{MgO}$
Explanation:
(B) : When magnesium metal is heated in nitrogen, it forms magnesium nitride. $3 \mathrm{Mg}+\mathrm{N}_{2} \rightarrow \mathrm{Mg}_{3} \mathrm{~N}_{2}$ Hydrolysis of magnesium nitride gives magnesium hydroxide and ammonia. $\mathrm{CuSO}_{4}+4 \mathrm{NH}_{3} \rightarrow\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{SO}_{4}$ $\mathrm{Mg}_{3} \mathrm{~N}_{2} \stackrel{\text { Water }}{\longrightarrow} \mathrm{Mg}(\mathrm{OH})_{2}+\mathrm{NH}_{3}$ When ammonia gas is dissolved in the copper sulphate solution blue colour is obtained.
Assam CEE-2014
COORDINATION COMPOUNDS
274412
The octahedral complex of a metal ion $\mathbf{M}^{3+}$ with four monodentate ligands $L_{1}, L_{2}, L_{3}$ and $L_{4}$ absorb wavelengths in the region of red, green, yellow and blue, respectively. The inreasing order of ligand strength of the four ligands is
(B) : $\begin{array}{lcccc}\text { Ligand : } \mathrm{L}_{1} \mathrm{~L}_{2} \mathrm{~L}_{3} \mathrm{~L}_{4} \\ \lambda_{\text {abs }} \text { Red } \text { Green } \text { Yellow } \text { Blue }\end{array}$ The order of Wavelength of absorption is Blue $<$ Green $<$ Yellow $<$ Red The order of splitting energy levels - $\mathrm{L}_{4}>\mathrm{L}_{2}>\mathrm{L}_{3}>\mathrm{L}_{1}$ Increasing order of ligand strength is - $\mathrm{L}_{1}<\mathrm{L}_{3}<\mathrm{L}_{2}<\mathrm{L}_{4}$
JEE Main 2014
COORDINATION COMPOUNDS
274414
Out of $\mathrm{TiF}_{6}^{2-}, \mathrm{CoF}_{6}^{3-}, \mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2-}(\mathrm{Z}$ of $\mathrm{Ti}=22, \mathrm{Co}=27, \mathrm{Cu}=29, \mathrm{Ni}=28)$ the colourless species are
1 $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2}$
2 $\mathrm{TiF}_{2}^{2-}$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$
3 $\mathrm{CoF}_{6}{ }^{3-}$ and $\mathrm{NiCl}_{4}{ }^{2-}$
4 $\mathrm{TiF}_{6}{ }^{2-}$ and $\mathrm{CoF}_{6}{ }^{3-}$
Explanation:
(B) : A species is coloured when it contain unpaired d-electron which are capable of undergoingd-d transition on absorption of light of a particular wavelength. In $\quad \mathrm{TiF}_{6}{ }^{2-} \quad \mathrm{Ti}^{4+}: 3 \mathrm{~d}^{0}$ colourless $\mathrm{CoF}_{6}{ }^{3-} \mathrm{Co}^{3+}: 3 \mathrm{~d}^{6}$ coloured $\mathrm{Cu}_{2} \mathrm{Cl}_{2} \quad \mathrm{Cu}^{+}: 3 \mathrm{~d}^{10}$ coloured $\mathrm{NiCl}_{4}^{2-} \quad \mathrm{Ni}^{2+}: 3 \mathrm{~d}^{8}$ colourless $\mathrm{TiF}_{6}{ }^{2-}\left(3 \mathrm{~d}^{0}\right)$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}\left(3 \mathrm{~d}^{10}\right)$ with empty and fully filled d-orbitals appear colourless as they are not capable by undergoing d-d transition.
AIPMT -2009
COORDINATION COMPOUNDS
274415
Which of the following complex ions is expected to absorb visible light?
1 $\left[\mathrm{Ti}(\text { en })_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]^{4+}$
(B) : Since $\mathrm{Cr}^{3+}$ in the complex has unpaired electrons in the d-orbital hence will be coloured. $\mathrm{Ti}=[\mathrm{Ar}] 3 \mathrm{~d}^{2} 4 \mathrm{~s}^{2}: \mathrm{Ti}^{4+}=3 \mathrm{~d}^{0}$ $\mathrm{Cr}=[\mathrm{Ar}] 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1} ; \mathrm{Cr}^{3+}=3 \mathrm{~d}^{3}$ $\mathrm{Zn}=[\mathrm{Ar}] 3 \mathrm{~d}^{10} 4 \mathrm{~s}^{2} ; \mathrm{Zn}^{2+}=3 \mathrm{~d}^{10}$ $\mathrm{Sc}=[\mathrm{Ar}] 3 \mathrm{~d}^{1} 4 \mathrm{~s}^{2} ; \mathrm{Sc}^{3+}=3 \mathrm{~d}^{0}$
AIPMT -2009
COORDINATION COMPOUNDS
274417
In which of the following pairs are both the ions coloured in aqueous solution? (At. no. : $\mathrm{Sc}=21, \mathrm{Ti}=22, \mathrm{Ni}=28, \mathrm{Cu}=29, \mathrm{Co}$ $=27$ )
274411
A metal $X$ on heating in nitrogen gas gives $Y . Y$ on treatment with $\mathrm{H}_{2} \mathrm{O}$ gives a colourless gas which when passed through $\mathrm{CuSO}_{4}$ solution gives a blue colour. $Y$ is
1 $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}$
2 $\mathrm{Mg}_{3} \mathrm{~N}_{2}$
3 $\mathrm{NH}_{3}$
4 $\mathrm{MgO}$
Explanation:
(B) : When magnesium metal is heated in nitrogen, it forms magnesium nitride. $3 \mathrm{Mg}+\mathrm{N}_{2} \rightarrow \mathrm{Mg}_{3} \mathrm{~N}_{2}$ Hydrolysis of magnesium nitride gives magnesium hydroxide and ammonia. $\mathrm{CuSO}_{4}+4 \mathrm{NH}_{3} \rightarrow\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{SO}_{4}$ $\mathrm{Mg}_{3} \mathrm{~N}_{2} \stackrel{\text { Water }}{\longrightarrow} \mathrm{Mg}(\mathrm{OH})_{2}+\mathrm{NH}_{3}$ When ammonia gas is dissolved in the copper sulphate solution blue colour is obtained.
Assam CEE-2014
COORDINATION COMPOUNDS
274412
The octahedral complex of a metal ion $\mathbf{M}^{3+}$ with four monodentate ligands $L_{1}, L_{2}, L_{3}$ and $L_{4}$ absorb wavelengths in the region of red, green, yellow and blue, respectively. The inreasing order of ligand strength of the four ligands is
(B) : $\begin{array}{lcccc}\text { Ligand : } \mathrm{L}_{1} \mathrm{~L}_{2} \mathrm{~L}_{3} \mathrm{~L}_{4} \\ \lambda_{\text {abs }} \text { Red } \text { Green } \text { Yellow } \text { Blue }\end{array}$ The order of Wavelength of absorption is Blue $<$ Green $<$ Yellow $<$ Red The order of splitting energy levels - $\mathrm{L}_{4}>\mathrm{L}_{2}>\mathrm{L}_{3}>\mathrm{L}_{1}$ Increasing order of ligand strength is - $\mathrm{L}_{1}<\mathrm{L}_{3}<\mathrm{L}_{2}<\mathrm{L}_{4}$
JEE Main 2014
COORDINATION COMPOUNDS
274414
Out of $\mathrm{TiF}_{6}^{2-}, \mathrm{CoF}_{6}^{3-}, \mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2-}(\mathrm{Z}$ of $\mathrm{Ti}=22, \mathrm{Co}=27, \mathrm{Cu}=29, \mathrm{Ni}=28)$ the colourless species are
1 $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2}$
2 $\mathrm{TiF}_{2}^{2-}$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$
3 $\mathrm{CoF}_{6}{ }^{3-}$ and $\mathrm{NiCl}_{4}{ }^{2-}$
4 $\mathrm{TiF}_{6}{ }^{2-}$ and $\mathrm{CoF}_{6}{ }^{3-}$
Explanation:
(B) : A species is coloured when it contain unpaired d-electron which are capable of undergoingd-d transition on absorption of light of a particular wavelength. In $\quad \mathrm{TiF}_{6}{ }^{2-} \quad \mathrm{Ti}^{4+}: 3 \mathrm{~d}^{0}$ colourless $\mathrm{CoF}_{6}{ }^{3-} \mathrm{Co}^{3+}: 3 \mathrm{~d}^{6}$ coloured $\mathrm{Cu}_{2} \mathrm{Cl}_{2} \quad \mathrm{Cu}^{+}: 3 \mathrm{~d}^{10}$ coloured $\mathrm{NiCl}_{4}^{2-} \quad \mathrm{Ni}^{2+}: 3 \mathrm{~d}^{8}$ colourless $\mathrm{TiF}_{6}{ }^{2-}\left(3 \mathrm{~d}^{0}\right)$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}\left(3 \mathrm{~d}^{10}\right)$ with empty and fully filled d-orbitals appear colourless as they are not capable by undergoing d-d transition.
AIPMT -2009
COORDINATION COMPOUNDS
274415
Which of the following complex ions is expected to absorb visible light?
1 $\left[\mathrm{Ti}(\text { en })_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]^{4+}$
(B) : Since $\mathrm{Cr}^{3+}$ in the complex has unpaired electrons in the d-orbital hence will be coloured. $\mathrm{Ti}=[\mathrm{Ar}] 3 \mathrm{~d}^{2} 4 \mathrm{~s}^{2}: \mathrm{Ti}^{4+}=3 \mathrm{~d}^{0}$ $\mathrm{Cr}=[\mathrm{Ar}] 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1} ; \mathrm{Cr}^{3+}=3 \mathrm{~d}^{3}$ $\mathrm{Zn}=[\mathrm{Ar}] 3 \mathrm{~d}^{10} 4 \mathrm{~s}^{2} ; \mathrm{Zn}^{2+}=3 \mathrm{~d}^{10}$ $\mathrm{Sc}=[\mathrm{Ar}] 3 \mathrm{~d}^{1} 4 \mathrm{~s}^{2} ; \mathrm{Sc}^{3+}=3 \mathrm{~d}^{0}$
AIPMT -2009
COORDINATION COMPOUNDS
274417
In which of the following pairs are both the ions coloured in aqueous solution? (At. no. : $\mathrm{Sc}=21, \mathrm{Ti}=22, \mathrm{Ni}=28, \mathrm{Cu}=29, \mathrm{Co}$ $=27$ )
274411
A metal $X$ on heating in nitrogen gas gives $Y . Y$ on treatment with $\mathrm{H}_{2} \mathrm{O}$ gives a colourless gas which when passed through $\mathrm{CuSO}_{4}$ solution gives a blue colour. $Y$ is
1 $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}$
2 $\mathrm{Mg}_{3} \mathrm{~N}_{2}$
3 $\mathrm{NH}_{3}$
4 $\mathrm{MgO}$
Explanation:
(B) : When magnesium metal is heated in nitrogen, it forms magnesium nitride. $3 \mathrm{Mg}+\mathrm{N}_{2} \rightarrow \mathrm{Mg}_{3} \mathrm{~N}_{2}$ Hydrolysis of magnesium nitride gives magnesium hydroxide and ammonia. $\mathrm{CuSO}_{4}+4 \mathrm{NH}_{3} \rightarrow\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{SO}_{4}$ $\mathrm{Mg}_{3} \mathrm{~N}_{2} \stackrel{\text { Water }}{\longrightarrow} \mathrm{Mg}(\mathrm{OH})_{2}+\mathrm{NH}_{3}$ When ammonia gas is dissolved in the copper sulphate solution blue colour is obtained.
Assam CEE-2014
COORDINATION COMPOUNDS
274412
The octahedral complex of a metal ion $\mathbf{M}^{3+}$ with four monodentate ligands $L_{1}, L_{2}, L_{3}$ and $L_{4}$ absorb wavelengths in the region of red, green, yellow and blue, respectively. The inreasing order of ligand strength of the four ligands is
(B) : $\begin{array}{lcccc}\text { Ligand : } \mathrm{L}_{1} \mathrm{~L}_{2} \mathrm{~L}_{3} \mathrm{~L}_{4} \\ \lambda_{\text {abs }} \text { Red } \text { Green } \text { Yellow } \text { Blue }\end{array}$ The order of Wavelength of absorption is Blue $<$ Green $<$ Yellow $<$ Red The order of splitting energy levels - $\mathrm{L}_{4}>\mathrm{L}_{2}>\mathrm{L}_{3}>\mathrm{L}_{1}$ Increasing order of ligand strength is - $\mathrm{L}_{1}<\mathrm{L}_{3}<\mathrm{L}_{2}<\mathrm{L}_{4}$
JEE Main 2014
COORDINATION COMPOUNDS
274414
Out of $\mathrm{TiF}_{6}^{2-}, \mathrm{CoF}_{6}^{3-}, \mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2-}(\mathrm{Z}$ of $\mathrm{Ti}=22, \mathrm{Co}=27, \mathrm{Cu}=29, \mathrm{Ni}=28)$ the colourless species are
1 $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2}$
2 $\mathrm{TiF}_{2}^{2-}$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$
3 $\mathrm{CoF}_{6}{ }^{3-}$ and $\mathrm{NiCl}_{4}{ }^{2-}$
4 $\mathrm{TiF}_{6}{ }^{2-}$ and $\mathrm{CoF}_{6}{ }^{3-}$
Explanation:
(B) : A species is coloured when it contain unpaired d-electron which are capable of undergoingd-d transition on absorption of light of a particular wavelength. In $\quad \mathrm{TiF}_{6}{ }^{2-} \quad \mathrm{Ti}^{4+}: 3 \mathrm{~d}^{0}$ colourless $\mathrm{CoF}_{6}{ }^{3-} \mathrm{Co}^{3+}: 3 \mathrm{~d}^{6}$ coloured $\mathrm{Cu}_{2} \mathrm{Cl}_{2} \quad \mathrm{Cu}^{+}: 3 \mathrm{~d}^{10}$ coloured $\mathrm{NiCl}_{4}^{2-} \quad \mathrm{Ni}^{2+}: 3 \mathrm{~d}^{8}$ colourless $\mathrm{TiF}_{6}{ }^{2-}\left(3 \mathrm{~d}^{0}\right)$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}\left(3 \mathrm{~d}^{10}\right)$ with empty and fully filled d-orbitals appear colourless as they are not capable by undergoing d-d transition.
AIPMT -2009
COORDINATION COMPOUNDS
274415
Which of the following complex ions is expected to absorb visible light?
1 $\left[\mathrm{Ti}(\text { en })_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]^{4+}$
(B) : Since $\mathrm{Cr}^{3+}$ in the complex has unpaired electrons in the d-orbital hence will be coloured. $\mathrm{Ti}=[\mathrm{Ar}] 3 \mathrm{~d}^{2} 4 \mathrm{~s}^{2}: \mathrm{Ti}^{4+}=3 \mathrm{~d}^{0}$ $\mathrm{Cr}=[\mathrm{Ar}] 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1} ; \mathrm{Cr}^{3+}=3 \mathrm{~d}^{3}$ $\mathrm{Zn}=[\mathrm{Ar}] 3 \mathrm{~d}^{10} 4 \mathrm{~s}^{2} ; \mathrm{Zn}^{2+}=3 \mathrm{~d}^{10}$ $\mathrm{Sc}=[\mathrm{Ar}] 3 \mathrm{~d}^{1} 4 \mathrm{~s}^{2} ; \mathrm{Sc}^{3+}=3 \mathrm{~d}^{0}$
AIPMT -2009
COORDINATION COMPOUNDS
274417
In which of the following pairs are both the ions coloured in aqueous solution? (At. no. : $\mathrm{Sc}=21, \mathrm{Ti}=22, \mathrm{Ni}=28, \mathrm{Cu}=29, \mathrm{Co}$ $=27$ )
274411
A metal $X$ on heating in nitrogen gas gives $Y . Y$ on treatment with $\mathrm{H}_{2} \mathrm{O}$ gives a colourless gas which when passed through $\mathrm{CuSO}_{4}$ solution gives a blue colour. $Y$ is
1 $\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}$
2 $\mathrm{Mg}_{3} \mathrm{~N}_{2}$
3 $\mathrm{NH}_{3}$
4 $\mathrm{MgO}$
Explanation:
(B) : When magnesium metal is heated in nitrogen, it forms magnesium nitride. $3 \mathrm{Mg}+\mathrm{N}_{2} \rightarrow \mathrm{Mg}_{3} \mathrm{~N}_{2}$ Hydrolysis of magnesium nitride gives magnesium hydroxide and ammonia. $\mathrm{CuSO}_{4}+4 \mathrm{NH}_{3} \rightarrow\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{SO}_{4}$ $\mathrm{Mg}_{3} \mathrm{~N}_{2} \stackrel{\text { Water }}{\longrightarrow} \mathrm{Mg}(\mathrm{OH})_{2}+\mathrm{NH}_{3}$ When ammonia gas is dissolved in the copper sulphate solution blue colour is obtained.
Assam CEE-2014
COORDINATION COMPOUNDS
274412
The octahedral complex of a metal ion $\mathbf{M}^{3+}$ with four monodentate ligands $L_{1}, L_{2}, L_{3}$ and $L_{4}$ absorb wavelengths in the region of red, green, yellow and blue, respectively. The inreasing order of ligand strength of the four ligands is
(B) : $\begin{array}{lcccc}\text { Ligand : } \mathrm{L}_{1} \mathrm{~L}_{2} \mathrm{~L}_{3} \mathrm{~L}_{4} \\ \lambda_{\text {abs }} \text { Red } \text { Green } \text { Yellow } \text { Blue }\end{array}$ The order of Wavelength of absorption is Blue $<$ Green $<$ Yellow $<$ Red The order of splitting energy levels - $\mathrm{L}_{4}>\mathrm{L}_{2}>\mathrm{L}_{3}>\mathrm{L}_{1}$ Increasing order of ligand strength is - $\mathrm{L}_{1}<\mathrm{L}_{3}<\mathrm{L}_{2}<\mathrm{L}_{4}$
JEE Main 2014
COORDINATION COMPOUNDS
274414
Out of $\mathrm{TiF}_{6}^{2-}, \mathrm{CoF}_{6}^{3-}, \mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2-}(\mathrm{Z}$ of $\mathrm{Ti}=22, \mathrm{Co}=27, \mathrm{Cu}=29, \mathrm{Ni}=28)$ the colourless species are
1 $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$ and $\mathrm{NiCl}_{4}^{2}$
2 $\mathrm{TiF}_{2}^{2-}$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}$
3 $\mathrm{CoF}_{6}{ }^{3-}$ and $\mathrm{NiCl}_{4}{ }^{2-}$
4 $\mathrm{TiF}_{6}{ }^{2-}$ and $\mathrm{CoF}_{6}{ }^{3-}$
Explanation:
(B) : A species is coloured when it contain unpaired d-electron which are capable of undergoingd-d transition on absorption of light of a particular wavelength. In $\quad \mathrm{TiF}_{6}{ }^{2-} \quad \mathrm{Ti}^{4+}: 3 \mathrm{~d}^{0}$ colourless $\mathrm{CoF}_{6}{ }^{3-} \mathrm{Co}^{3+}: 3 \mathrm{~d}^{6}$ coloured $\mathrm{Cu}_{2} \mathrm{Cl}_{2} \quad \mathrm{Cu}^{+}: 3 \mathrm{~d}^{10}$ coloured $\mathrm{NiCl}_{4}^{2-} \quad \mathrm{Ni}^{2+}: 3 \mathrm{~d}^{8}$ colourless $\mathrm{TiF}_{6}{ }^{2-}\left(3 \mathrm{~d}^{0}\right)$ and $\mathrm{Cu}_{2} \mathrm{Cl}_{2}\left(3 \mathrm{~d}^{10}\right)$ with empty and fully filled d-orbitals appear colourless as they are not capable by undergoing d-d transition.
AIPMT -2009
COORDINATION COMPOUNDS
274415
Which of the following complex ions is expected to absorb visible light?
1 $\left[\mathrm{Ti}(\text { en })_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]^{4+}$
(B) : Since $\mathrm{Cr}^{3+}$ in the complex has unpaired electrons in the d-orbital hence will be coloured. $\mathrm{Ti}=[\mathrm{Ar}] 3 \mathrm{~d}^{2} 4 \mathrm{~s}^{2}: \mathrm{Ti}^{4+}=3 \mathrm{~d}^{0}$ $\mathrm{Cr}=[\mathrm{Ar}] 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1} ; \mathrm{Cr}^{3+}=3 \mathrm{~d}^{3}$ $\mathrm{Zn}=[\mathrm{Ar}] 3 \mathrm{~d}^{10} 4 \mathrm{~s}^{2} ; \mathrm{Zn}^{2+}=3 \mathrm{~d}^{10}$ $\mathrm{Sc}=[\mathrm{Ar}] 3 \mathrm{~d}^{1} 4 \mathrm{~s}^{2} ; \mathrm{Sc}^{3+}=3 \mathrm{~d}^{0}$
AIPMT -2009
COORDINATION COMPOUNDS
274417
In which of the following pairs are both the ions coloured in aqueous solution? (At. no. : $\mathrm{Sc}=21, \mathrm{Ti}=22, \mathrm{Ni}=28, \mathrm{Cu}=29, \mathrm{Co}$ $=27$ )
