The reaction(s) involved in the preparation of potassium dichromate from iron chromite ore is/are:

1.	FeCr2O4 + NaOH + O2 → Na2CrO4 + Fe2O3 + H2O
2.	Na2CrO4 + H2SO4 (conc.) → Na2Cr2O7 + Na2SO4 + H2O
3.	Na2Cr2O7 + KCl→ K2Cr2O7 + NaCl
4.	All of the above.

For M²⁺/M, and M³⁺/M²⁺, the $\mathrm{E}°$ values of some metals are given in the table below:

The correct inference(s) from the above data is/are: 

Consider the following graph.

Based on the graph above, it can be concluded that the element with a melting point higher than 3000 K will be:

Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of: 

The correct statement(s) about transition elements are:  

Match the List I with List II:

Transition metals and their many compounds act as good catalysts due to :

The transition metals generally form coloured compounds due to :

The enthalpy of atomization of transition metals is high due to :

1. High effective nuclear charge

2. A large number of valence electrons

3. Very strong metallic bonds

4. All of the above

The correct statement regarding the element silver(Ag) is: