Bacterial pathogens most commonly use this class of metabolism. what are these pathogens?

Most pathogenic bacteria are chemoheterotrophs. This means:

•Chemo - they obtain energy by the oxidation of electron donors (get their energy from chemical reactions, unlike phototrophs which use solar energy.  

•Heterotrophs – they are unable to fix carbon to form their own organic compounds so they use organic (chemoorganoheterotrophs)  or inorganic (chemolithoheterotrophs) components as energy sources.

idk what the options are but

these is a strong electrostatic attraction between the ions hence a lot of energy is needed to overcome this attraction

this is why the boiling points are so high