Cr₂O₇^2-+X$\stackrel{{\mathrm{H}}^{+}}{\to }$Cr³⁺+H₂O + oxidized product of X. X in the above reaction cannot be

1. C₂O₄^2-

2. Fe²⁺

3. SO₄^2-

4. S^2-

Basic oxide amongst the following is:

1. CrO

2. Cr₂O₃

3. CrO₃

4. Cr₂O₄

A pair of ions having similar magnetic moments is:

1. Ti³⁺,V³⁺

2. Cr³⁺,Mn²⁺

3. Mn²⁺,Fe³⁺

4. Fe²⁺,Mn²⁺

Lanthanoid which is radioactive is

1. Promethium

2. Europium

3. Plutonium

4. Neptunium

Actinide contraction is mainly related to:

From the following, which is the most basic hydroxide?

1. Ce(OH)₃

2. Lu(OH)₃

3. Yb(OH)₃

4. Tb(OH)₃

Which is colorless in water?

1. Ti³⁺

2. V³⁺

3. Cr³⁺

4. Sc³⁺

CrO₄^2- and MnO₄^- are strong yellow and intense purple  respectively in aqueous solution The darkening of colour is due to

1. charge transfer

2. d-d transition

3. half-filled d-sub shells

4. increasing number of unpaired electron

In the dichromate ion Cr₂O₇^2-,

1. 4 Cr-O bonds are equivalent

2. 6 Cr-O bonds are equivalent

3. All Cr-O bonds are equivalent

4. None of Cr-O bonds are equivalent

Electronic configuration of a transition element X in +3 Oxidation state is [Ar]3d⁵.

What is its atomic number?

1. 25

2. 26

3. 27

4. 24