**Question:** ORS contains 75 m mol/litre -

A. 25 m mol/L of glucose
B. 25 m mol/L of sodium
C. 25 m mol/L of potassium
D. 15 m mol/L of chloride

**Correct Answer:**

**Core Concept:** ORS (Organic Acid Replacement Solution) is a solution used for rehydration therapy in cases of dehydration, particularly in children suffering from diarrhea and vomiting. It helps replace essential ions and fluids lost due to increased intestinal permeability and water loss in diarrhea.

**Why the Correct Answer is Right:** ORS contains 75 m mol/L of glucose, which acts as a potent osmotic agent to attract water into the intestines, thus aiding in rehydration. The high glucose concentration ensures rapid rehydration without causing a significant rise in blood glucose levels.

**Why Each Wrong Option is Incorrect:**

A. 25 m mol/L of glucose (Option A) is not enough to achieve the desired osmotic effect, making it an incorrect choice.
B. 25 m mol/L of sodium (Option B) is not the primary component responsible for rehydration but is included for electrolyte balance.
C. 25 m mol/L of potassium (Option C) might be too high, potentially causing hyperkalemia in some cases.
D. 15 m mol/L of chloride (Option D) is included for electrolyte balance but does not contribute significantly to the rehydration process.

**Clinical Pearl:** A well-formulated ORS should contain appropriate concentrations of glucose, sodium, potassium, and chloride ions to ensure effective rehydration while maintaining electrolyte balance. The correct concentrations help achieve rapid, safe rehydration in patients suffering from dehydration caused by diarrhea and vomiting.