What happens to an elodea cell when the leaf is mounted in regular tap water?

When an Elodea leaf cell is mounted in regular tap water, it generally experiences a state of turgor pressure. The water enters the cell through osmosis, causing the central vacuole to swell and push the cell membrane against the rigid cell wall. This results in a firm and turgid cell, which helps maintain the structural integrity of the plant. If the water is hypotonic, the cells will remain healthy; however, if the water is excessively saline or has other impurities, it could lead to plasmolysis.