Step 1: Understanding the Concept:
Epsom salt is a common inorganic compound used in medicine as a saline purgative (laxative) and for treating magnesium deficiency.
Step 2: Detailed Explanation:
1. Chemical Identity: Epsom salt is the common name for Magnesium Sulphate heptahydrate (\(MgSO_4 \cdot 7H_2O\)).
2. Use: In the digestive tract, it acts by osmotic pressure, drawing water into the intestines to induce defecation. It is also used in "Epsom baths" for muscle relaxation.
3. Others: Calcium sulphate is Gypsum; Sodium sulphate is Glauber's salt.
Step 3: Final Answer:
Epsom salt is chemically identified as Magnesium Sulphate.