If we sprinkle common salt on an earth worm, it dies due to

Earthworms belong to the phylum Annelida and possess a highly permeable, moist skin essential for gas exchange [c1, t1]. When common salt (NaCl) is sprinkled on their skin, it creates a hypertonic environment relative to the earthworm's internal fluids. This triggers a process known as osmosis, where water rapidly moves out of the earthworm's body to balance the salt concentration [t6]. This sudden and massive loss of water leads to 'osmotic shock' and severe dehydration [t5, t6]. Because earthworms rely on a moist skin surface to dissolve oxygen for respiration, the resulting desiccation prevents gas exchange, ultimately leading to death [c1, t1]. While the lack of moisture affects breathing, the primary physiological trigger caused by the salt application is the osmotic imbalance and subsequent fluid loss.

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 9: Life Processes in Animals > 9.2.2 Do other animals breathe the same way as humans do? > p. 133
2. [2] https://www.sciencedirect.com/topics/immunology-and-microbiology/enchytraeidae