The hybridization of orbitals of N atom in $$NO_3^-$$, $$NO_2^+$$ and $$NH_4^+$$ are respectively :

The structure of IF₇ is :

'a’ and `b’ are van der Waals’ constants for gases. Chlorine is more easily liquefied than ethane because

The entropy change involved in the isothermal reversible expansion of 2 moles of an ideal gas from a volume of 10 dm³ to a volume of 100 dm³ at 27^oC is :