Ion that gives colour to water is:

1. $C{u}^{+}$

2. $C{r}^{3+}$

3. $N{a}^{+}$

4. None of the above.

Which of the following is a coloured and paramagnetic compound?

1. CuF₂

2. K₂Cr₂O₇

3. $KMn{O}_4$

4. K₄[Fe(CN)₆]

Compound 'A' in acidic medium does not give ppt with $H_{2}S$ but in $N{H}_{4}OH$ medium gives a ppt comp. 'A' is:

1. $FeC{l}_3$

2. $AlC{l}_3$

3. $ZnC{l}_2$

4. $SnC{l}_2$

Chromite ore (FeCr₂O₄) is fused with sodium carbonate (Na₂CO₃) in the presence of air (oxygen). The reaction is part of the industrial extraction of chromium.

The major chromium-containing product X formed in the reaction FeCr₂O₄ + Na₂CO₃ → X
(along with other products like Fe₂O₃ and CO₂) is:

Colourless ion among the following is:

An element among the following that exhibits the maximum oxidation state is:

1. Cr

2. Mn

3. Fe

4. V

An element among the following that shows the maximum number of oxidation states is:

1. Cr

2. Fe

3. Mn

4. V

Zn gives H₂ gas with H₂SO₄ and HCl but not with HNO₃ because:
 

Which of the following factors is primarily responsible for the catalytic activity of transition metals?

The basic character of the transition metal monoxides follows the order:
(Atomic nos. Ti = 22, V = 23, Cr = 24, Fe = 26)