The addition of one electron in ${\mathrm{O}}_2$ gives ${\mathrm{O}}_2^{-}$ while the removal of one electron gives ${\mathrm{O}}_2^{+}$. Which of the following facts is correct for ${\mathrm{O}}_2^{+}$ and ${\mathrm{O}}_2^{-}$ species relative to ${\mathrm{O}}_2$ molecule?

Explain the following:

Salt-like ${\mathrm{KHF}}_2$ is stable but ${\mathrm{KHCl}}_2$ is not known.

Explain the following:

${\mathrm{H}}_3{\mathrm{PO}}_4$ is a syrupy liquid.

Explain the following:

${\mathrm{H}}_2{\mathrm{SO}}_4$ is a colourless, viscous oily liquid and has a high boiling point.