$${K_{{a_1}}}$$, $${K_{{a_2}}}$$ and $${K_{{a_3}}}$$ are the respective ionization constants for the following reactions (a), (b) and (c).

(a) $${H_2}{C_2}{O_4} \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} {H^ + } + H{C_2}O_4^ - $$

(b) $$H{C_2}O_4^ - \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} {H^ + } + {C_2}O_4^{2 - }$$

(c) $${H_2}{C_2}O_4^{} \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} 2{H^ + } + {C_2}O_4^{2 - }$$

The relationship between $${K_{{a_1}}}$$, $${K_{{a_2}}}$$ and $${K_{{a_3}}}$$ is given as :

The molar conductivity of a conductivity cell filled with 10 moles of 20 mL NaCl solution is $${\Lambda _{m1}}$$ and that of 20 moles another identical cell heaving 80 mL NaCl solution is $${\Lambda _{m2}}$$. The conductivities exhibited by these two cells are same. The relationship between $${\Lambda _{m2}}$$ and $${\Lambda _{m1}}$$ is

The first ionization enthalpies of Be, B, N and O follow the order

The correct order of energy of absorption for the following metal complexes is :

A : [Ni(en)₃]²⁺ , B : [Ni(NH₃)₆]²⁺ , C : [Ni(H₂O)₆]²⁺