Question

Bleeding caused by a nick from a razor during shaving can be stopped by rubbing alum. Give a reason.

Answer 1

Bleeding caused by a razor nick stops when rubbed with alum because it coagulates the blood. Blood is a colloidal solution, and alum causes its proteins to coagulate, forming a clot that blocks the wound and stops bleeding. Hence, alum acts as a styptic agent to stop bleeding quickly.