Chemical reaction takes place when iron is added copper sulphate solution but no reaction takes place when copper dust is added into ferrous sulphate solution .Why?Describe in brief the effect of physical state of reactants in chemical reaction.​

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.

Ithink carbon dioxide, i am not completely sure.tell me if i am wrong.