Iron does not get oxidised in:

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 a high temperature

The incorrect statement among the following is:  

The oxidation state of chromium in the final product formed by the reaction between KI and acidified potassium dichromate solution will be:

1. +2

2. +3

3. +4

4. +6

The lanthanide contraction is responsible for the fact that:

1. Zr and Y have about the same radius .

2. Zr and Zn have the same oxidation state.  

3. Zr and Hf have about the same atomic radius .

4. Zr and Nb have a similar oxidation state.

Actinoids show a greater number of oxidation states than lanthanoids because:  

Match the following characteristics to the appropriate metal:  

Select the correct option :

Urea reacts with water to form A, which decomposes to form B. When B is passed through ${\mathrm{Cu}}^{2+}$ (aq), a deep blue-colored solution C is formed

The formula of C is: 

1. ${\left[\mathrm{Cu}{\left({\mathrm{NH}}_3\right)}_4\right]}^{2+}$

2. $\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$

3. ${\mathrm{CuCO}}_3.\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$

4. ${\mathrm{CuSO}}_4$

Among the following, which are amphoteric oxides?

1. V₂O₅, Cr₂O₃
2. Mn₂O₇, CrO₃
3. CrO, V₂O₅
4. V₂O₅, V₂O₄

Highest oxidation state of manganese in fluoride is +4 (Mn$F_4$) but the highest oxidation state in oxides is +7 (Mn₂O₇). The reason is :

The values of X, Y, P, and Q are, respectively:
   

1. ${\mathrm{MnO}}_3^{+}$, Mn₂O₇, conc. H₂SO₄, and K₂MnO₄

2. K₂MnO₄, conc. H₂SO₄, Mn₂O₇, and ${\mathrm{MnO}}_3^{+}$

3. Na₂CO₃, MnO₂, K₂MnO₄, and Mn₂O₇

4. H⁺, K₂MnO₄, ${\mathrm{MnO}}_3^{+}$, and Mn₂O₇