Which of the follow can NOT be possible error that occurs during a lab experiment?
human error
pure reactants were used
thing
O unexpected products were produced
the reaction didn't go to completion

They are all decomposition reactions.

Neither model is able to show the reactivity of potassium.

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.