The correct order of second ionisation potential of carbon, nitrogen, oxygen and fluorine is

The angle between two convalent bonds is maximum in ________. (CH₄, H₂O, CO₂)

If a molecule MX₃ has zero dipole moment, the sigma bonding orbitals used by M (atomic number < 21) are

Equal weights of methane and oxygen are mixed in an empty container at 25^oC. The fraction of the total pressure exerted by oxygen is