Which solution is the most concentrated?

2.0 ml of 10 m h2so4, where h2so4 has a molar mass of 98 g/mol
5.0 ml of 1.0 m pbso4, where pbso4 has a molar mass of 303 g/mol
2.0 ml of 10.5 m h2o2, where h2o2 has a molar mass of 34 g/mol
100 ml of 10 m nacl, where nacl has a molar mass of 58 g/mol

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.

The closer the atoms are to becoming ionic the more highly dense the negatively charged side gets.

The water cycle increase the water content in the earth atmosphere