Which one of the following ions exhibits d–d transition and paramagnetism as well?

1. ${\mathrm{CrO}}_4^{2-}$

2. ${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}$

3. ${\mathrm{MnO}}_4^{-}$

4. ${\mathrm{MnO}}_4^{2-}$

 

Which one of the following statements is correct when SO₂ is passed through acidified K₂Cr₂O₇solution?

1. The solution is decolorized.

2. SO₂ is reduced.

3. Green coloured Cr₂(SO₄)₃ is formed.

4. The solution turns blue.

Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?

1. $\left[Xe\right]4 f^8 6d^2$

2. $\left[Xe\right]4 f^9 5s^1$

3. $\left[Xe\right]4 f^7 5d^{1}6s^2$

4. $\left[Xe\right]4 f^6 5d^{2}6s^2$

Assuming complete ionization, same moles of which of the following compounds will require the the least amount of acidified KMnO₄ for complex oxidation?

1. $FeS{O}_4$

2. $FeS{O}_3$

3. $Fe{C}_2{O}_4$

4. $Fe{\left(N{O}_2\right)}_2$

Magnetic moment 2.84 BM is given by (At. no. Ni = 28, Ti = 22, Cr = 24, Co = 27)

$1. {\mathrm{Ni}}^{2+}$
$2. {\mathrm{Ti}}^{3+}$
$3. {\mathrm{Cr}}^{3+}$
$4. {\mathrm{Co}}^{2+}$

Identify the alloy containing a non-metal as a constituent in it.

1. Invar

2. Steel

3. Bell metal

4. Bronze

1.  Fe>Mn>Co>Cr

2.  Co>Mn>Fe>Cr

3.  Cr>Mn>Co>Fe

4.  Mn>Fe>Cr>Co

The acidified \(\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7\) solution turns green when \(\mathrm{Na}_2 \mathrm{SO}_3\) is added to it. This is due to the formation of: