Why pure alcohol is less effective than aqueos alcohol?

Pure alcohol is less effective than aqueous alcohol because the presence of water enhances the alcohol's ability to penetrate cell membranes and disrupt cellular structures. Aqueous alcohol solutions, typically around 60-80% alcohol, allow for better protein denaturation and microbial cell lysis, making them more effective as disinfectants. Additionally, water acts as a solvent that helps in the effective distribution and contact time of the alcohol on surfaces. Thus, the combination of water and alcohol optimizes the antimicrobial action.