In what phase is the substance at 50 0C and 1 atm pressure? At what pressure and temperature conditions will all three phases of the substance be present?

What is the normal melting point of the substance?

What phase(s) will exist at 1 atm and 70 0C?

Ions gain or lose electrons

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.