The correct order of E⁰(M²⁺/M) values with a negative sign for the four successive elements Cr, Mn, Fe and Co is

1. Mn > Fe > Co > Cr

2. Mn > Cr > Fe > Co

3. Fe > Mn > Cr > Co

4. Co > Fe > Mn > Cr

Which of the following lanthanoid elements is regarded as the hardest?

1. Lanthanum (La)
2. Lutetium (Lu)
3. Samarium (Sm)
4. Ytterbium (Yb)

The unpaired  electron in Eu³⁺ will be the same in: 

1. Yb²⁺

2. Ho³⁺

3. Sm²⁺

4. Gd³⁺

Primary component of Mischmetal that is commonly utilised in gas lighters is:

1. Cerium 
2. Iron
3. Samarium
4. Lanthanum

The correct statement is

1. Green vitriol and blue vitriol are isomorphus

2. KMnO₄ and K₂Cr₂O₇ are coloured due to d-d transitions

3. Cu₂Cl₂ and Ag₂S are coloured

4. Upon strong heating paramagnetic gases are evolved by CuSO₄ and AgNO₃

Which is true about the ionic radius of M²⁺?

1. Ni²⁺<Cu²⁺<Zn²⁺

2. Ni²⁺>Cu²⁺>Zn²⁺

3. Cu²⁺<Ni²⁺<Zn²⁺

4. Zn²⁺<Ni²⁺<Cu²⁺

Which of the following will not give a positive chromyl chloride test?

(1) CuCl₂

(2) ZnCl₂

(3) HgCl₂

(4) NH₄Cl

Which of the following can not exist together in aqueous solution?

1. HgCl₂ and SnCl₂

2. HgCl₂ and SnCl₄

3. SnCl₄ and FeCl₃

4. SnCl₄ and PbCl₄

A substance is found to have a magnetic moment of 3.9 B.M. The ion may be 

1. Fe⁺³

2. Mn⁺²

3. Co⁺²

4. Cu⁺²

The inner transition element is not represented by the atomic
number among 59, 74, 95, 102, and 104.

1. 59

2. 95

3. 102

4. 104