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:

A colored ion in aqueous solutions among the following is:

1. La³⁺ (Z=57)

2. Ti³⁺ (Z=22)

3. Lu³⁺ (Z=71)

4. Sc³⁺ (Z=21)

The species that are colourless:

(Z of Ti = 22, Co=27, Cu = 29, Ni= 28)

1. ${\mathrm{TiF}}_6^{2-}$ $\mathrm{and}$ ${\mathrm{CoF}}_6^{3-}$

2. ${\mathrm{Cu}}_2{\mathrm{Cl}}_2$ $\mathrm{and}$ ${\mathrm{NiCl}}_4^{2-}$

3. ${\mathrm{TiF}}_6^{2-}$ $\mathrm{and}$ ${\mathrm{Cu}}_2{\mathrm{Cl}}_2$

4. ${\mathrm{CoF}}_6^{3-}$ $\mathrm{and}$ ${\mathrm{NiCl}}_4^{2-}$