Cierta cantidad de Oxido de magnesio ocupa un volumen de 2500mL a una presión de 320 Torr y a una temperatura de 70ºC. ¿Cuál será su volumen si la presión y la temperatura se mantienen a condiciones normales?

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.

Answer (b) supersaturation;

Well you can immediately rule out a and d because if a metal were to lose or gain protons, then it would become a different element all together. the answer here is b because the positive symbol with a number refers to how many electrons the metal can give away to become stable.