($n - 1)\;d -$orbitals

($n - 2)\;f$-orbitals

($n - 1)\;d$-orbitals and ($n -$1) $f$-orbitals

($n - 1)\;d$-orbitals and $ns -$orbitals

${\left( {{\rm{N}}{{\rm{H}}_4}} \right)_2}{\rm{Mo}}{{\rm{O}}_4}$

$\left( {{\rm{N}}{{\rm{H}}_4}} \right){\rm{Mo}}{{\rm{O}}_2}$

${\left( {{\rm{N}}{{\rm{H}}_4}} \right)_2}{\rm{Mo}}{{\rm{O}}_3}$

${\rm{N}}{{\rm{H}}_4}.12{\rm{Mo}}{{\rm{O}}_3}$

Yb$^{3+}$

Tm$^{3+}$

Er$^{3+}$

None of these

Zn acts as an oxidising agent when react with ${\rm{HN}}{{\rm{O}}_3}$

${\rm{HN}}{{\rm{O}}_3}$ is weaker acid than ${{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}$ and HCl

In electrochemical series Zn is above hydrogen

${\rm{NO}}_3^ -$ ion is reduced in preference to hydronium ion

0

$1.87$

$5.92$

2

13 electrons have spin in one direction and 16 electrons in other direction

14 electrons have spin in one direction and 15 electrons in other direction

All the electrons have spin in one direction

None of the above

Ce⁴⁺, Yb²⁺

Gd³⁺, Tb⁴⁺

Eu²⁺, Lu³⁺

Ce⁴⁺, Eu²⁺

Fe

Ra

Co

All of these

Yellow

White

Brown

Black

${\rm{Cu}}{\left( {{\rm{OH}}} \right)_2}.2{\rm{CuC}}{{\rm{O}}_3}$

${\rm{CuS}}{{\rm{O}}_4}.3{\rm{Cu}}{\left( {{\rm{OH}}} \right)_2}$

${\rm{Cu}}{\left( {{\rm{OH}}} \right)_2}.{\rm{CuC}}{{\rm{O}}_3}$

${\rm{CuFe}}{{\rm{S}}_2}$

All the transition elements exhibit variable oxidation states

All the transition elements form colored compounds

All the transition elements are paramagnetic

All the transition elements form complex compounds