Question

How many grams of NaCl are dissolved in 250 grams of normal saline solution

Answer 1

Since, Normal Saline Solution is 0.91% w.v solution of NaCl which means the solution should contain 0.91% of NaCl by weight, for which take the 0.91% of total volume (250ml)-(I think you have mistaken, it must be 250ml not gms, since solution is measured in ml, litre etc.

Solution:
Amount of NaCl required in gms = 0.91% of Volume of solution,
Amount of NaCl required in gms = 0.91% of 250
Amount of NaCl required in gms = 2.27grams.

Hope it helps.

Answer 2

Normal saline contains 0.91% w/v of NaCl, meaning mass/volume, or 0.91grams of NaCl per 100 ml of solution. The sterile form of this saline is used for IV drips.

Other concentrations are also available.

This w/v unit is convenient to obtain mass by measuring volume, especially useful in medical situations where measuring volume is much faster than measuring mass.