Electrolysis of water containing sulfuric acid as an electrolyte is carried out as shown and the gases produced at the electrodes
collected in two identical tubes, both initially filled with the sulfuric acid solution. After electrolysis has been carried out for a
certain time, which picture best represents the appearance of the tubes?

The answers is a nuclear changes

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.