In the sixth period, the orbitals that are filled are :

The potential energy curve for the H₂ molecule as a function of internuclear distance is :

A diatomic molecule X₂ has a body-centred cubic (bcc) structure with a cell edge of 300 pm. The density of the molecule is 6.17 g cm^–3. The number of molecules present in 200 g of X₂ is :
(Avogadro constant (N _A) = 6 $$ \times $$ 10²³ mol^–1 )

The minimum number of moles of O₂ required for complete combustion of 1 mole of propane and 2 moles of butane is _____.