Q. No.Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
| 1. | \(\text{ [Xe] } 4f^8 6 d^2\) | 2. | \(\text { [Xe]}4 f^9 5 s^1\) |
| 3. | \(\text { [Xe] } 4f^7 5 d^1 6 s^2\) | 4. | \(\text { [Xe]} 4f^6 5 d^2 6 s^2\) |
Assuming complete ionization, same moles of which of the following compounds will require the least amount of acidified KMnO4 for complex oxidation?
1.
2.
3.
4.
A pair among the following have nearly the same atomic radii:
(Numbers in the parenthesis are atomic numbers).
| 1. | Ti (22) and Zr (40) | 2. | Zr (40) and Nb (41) |
| 3. | Zr (40) and Hf (72) | 4. | Zr (40) and Ta (73) |
Which of the following processes does not involve the oxidation of iron?
| 1. | Rusting of iron sheets |
| 2. | Decolourisation of blue CuSO4 solution by iron |
| 3. | Formation of Fe(CO)5 from Fe |
| 4. | Liberation of H2 from steam by iron at high temperature |
The pair of compounds that can exist together is:
1. FeCl3, SnCl2
2. HgCl2, SnCl2
3. FeCl2, SnCl2
4. FeCl3, Kl
In acidic medium, H2O2 changes Cr2O7–2 to CrO5 which has two (–O – O–) bonds.
The oxidation state of Cr in CrO5 is:
1. +5
2. +3
3. +6
4. -10
The reason for the lanthanoid contraction is:
1. negligible screening effect of 'f' orbitals.
2. increasing nuclear charge.
3. decreasing nuclear charge.
4. decreasing screening effect.
2. Na2S > CuS > ZnS
3. Na2S > ZnS > Cus
4. Cus > ZnS > Na2S
(At nos. Ce = 58, Sm = 62, Eu = 63, Yb = 70)
1. Sm2+
2. Eu2+
3. Yb2+
4. Ce2+
3 MnO 42– + 2 H 2 O ⇌ 2 MnO 4– + MnO 2 + 4 OH–
The reagent that facilitates the removal of OH– ions to ensure the completion of the conversion of K2MnO4 to KMnO4 is:
1. KOH
2. CO2
3. SO2
4. HCl
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