Question:easy
What is the osmolarity of the new (reduced osmolarity) ORS in mmol per litre?
What is the osmolarity of the new (reduced osmolarity) ORS in mmol per litre?
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The reduced osmolarity formula sums sodium, glucose, chloride, potassium and citrate.
Updated On: Jun 24, 2026
- 270
- 245
- 290
- 310
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The Correct Option is B
Solution and Explanation
Step 1: Distinguish the two generations of ORS. The earlier WHO formula sat near 310 mmol per litre, while the modern one was deliberately made hypo-osmolar.
Step 2: Lowering sodium and glucose brought the total down to 245 mmol per litre, which improved tolerance and cut stool volume in diarrhoea, especially in children.
Step 3: You can confirm 245 by adding the components: sodium 75, glucose 75, chloride 65, potassium 20 and citrate 10, which together give 245 mmol per litre.
Step 4: So the figure for the reduced osmolarity ORS is the second option, not the older 310 value or the unrelated 270 and 290 numbers.
\[\boxed{245 \text{ mmol/L}}\]
Step 2: Lowering sodium and glucose brought the total down to 245 mmol per litre, which improved tolerance and cut stool volume in diarrhoea, especially in children.
Step 3: You can confirm 245 by adding the components: sodium 75, glucose 75, chloride 65, potassium 20 and citrate 10, which together give 245 mmol per litre.
Step 4: So the figure for the reduced osmolarity ORS is the second option, not the older 310 value or the unrelated 270 and 290 numbers.
\[\boxed{245 \text{ mmol/L}}\]
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