Question

how does bleaching powder disinfects drinking water to make it free of germs

Answer 1

Bleaching powder as water disinfectant:
When bleaching powder dissolves, it reacts with water to hypochlorus acid (HOCl) and hypochlorite ions (OCl^-). The cell wall of pathogenic microorganisms is negatively charged by nature. As such, it can be penetrated by the neutral hypochlorus acid, rather than by the negatively charged hypochlorite ion. Hypochlorus acid can penetrate cell walls and protective layers of microorganisms and as a result kills pathogens . The microorganisms may also suffer from reproductive failure.