Assertion : The transition elements form interstitial compounds.

Reason: Steel and cast iron are hard due to the formation of an interstitial compound with carbon.

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

When iron becomes passive by "X", it is due to the formation of "Y". X and Y, respectively, are:

1. Dil. HCl, ${\mathrm{Fe}}_2{\mathrm{O}}_3$

2. 80% Conc. ${\mathrm{HNO}}_3$, ${\mathrm{Fe}}_3{\mathrm{O}}_4$

3. Conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$, ${\mathrm{Fe}}_3{\mathrm{O}}_4$

4. Conc. HCl, ${\mathrm{Fe}}_3{\mathrm{O}}_4$

When KMnO₄ solution is added to hot oxalic acid solution, the decolorization is slow in the beginning but becomes instantaneous after some time. This is because : 

1. ${\mathrm{Mn}}^{2+}$ acts as auto catalyst.

2. ${\mathrm{CO}}_2$ is formed.

3. Reaction is exothermic.

4. ${\mathrm{MnO}}_4^{-}$ catalyses the reaction.

Which of the following statements is false? 

The addition of non-metals like B and C to the interstitial sites of a transition metal increases

1. Ductility

2. Melting Point

3. Shining

4. Conductivity

Which of the following metals does not form amalgam?

1. Fe

2. Au

3. Zn

4. Ag

The element of the first transition series having lowest oxidation potential value $(\mathrm{M}\to {\mathrm{M}}^{2+}+2{\mathrm{e}}^{-})$ is -

1. Mn

2. Fe

3. Ni

4. Cu

The incorrect statement among the following about the chemistry of 3d and 4f series elements is 

Which of the following elements has the strongest metallic bond?

The ionization potential values of d-block elements as compared to the ionization potential values of f-block elements are: