In: Nursing
Required concentration and volume of dextrose solution is
1 litre of 20% dextrose solution.
This is a w/v% as dextrose solutions are graded that way.
So, 20% w/v% is 20 grams dextrose in 100ml. For 1000 ml of same
concentration, it is 200grams dextrose.
Available solution in pharmacy is 50%.
So 50% means 50 grams dextrose in 100ml of solution.
As total required dextrose is 200 grams, 200 grams will be present in 400ml of this solution.
The dextrose component is solved. Now volume of solution here is just 400ml. We need 600ml more to get required 1000ml.
So add 600ml of sterile water to this 400 ml of 50% dextrose solution.
The resultant solution will have 200 grams dextrose in 1000ml
solution.
To confirm it's concentration, it will be (200/1000) x 100 = 20%,
as required.
In short the instruction to the technicishould be "Take 400
ml of the available 50% dextrose solution and add 600ml of sterile
water to it".
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