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.
2.
3.
4.
A pair among the following have nearly the same atomic radii:
(Numbers in the parenthesis are atomic numbers).
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 number of d-electrons in Fe2+ (Z = 26) is not equal to the number of:
1. s-electrons in Mg (Z = 12)
2. p-electrons in Cl (Z = 17)
3. d-electrons in Fe (Z = 26)
4. p-electrons in Ne (Z = 10)
The pair of compounds that can exist together is:
1. FeCl3, SnCl2
2. HgCl, 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
2. Na2S > CuS > ZnS
3. Na2S > ZnS > Cus
4. Cus > ZnS > Na2S
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
Which of the following statements is false?
| 1. | On passing H2S through acidified K2Cr2O7 solution, a milky colour is observed. |
| 2. | Na2Cr2O7 is preferred over K2Cr2O7 in volumetric analysis. |
| 3. | K2Cr2O7 solution in an acidic medium is orange. |
| 4. | K2Cr2O7 solution becomes yellow in increasing the pH beyond 7 |
For the four successive transition elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order?
(At. No Cr= 24, Mn= 25, Fe=26, Co= 27)
1. Fe>Mn>Co>Cr
2. Co>Mn>Fe>Cr
3. Cr>Mn>Co>Fe
4. Mn>Fe>Cr>Co
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