How long the alcoholic cotton is placed on the puncture give reason?

Alcoholic cotton should typically be placed on the puncture site for about 30 seconds to 1 minute. This duration allows sufficient time for the alcohol to disinfect the area effectively, reducing the risk of infection. Leaving it on longer may cause skin irritation or dryness, while a shorter duration may not provide adequate sterilization. Always ensure the area is dry before proceeding with any medical procedure.