To make physiological saline, approximately how many grams of sodium chloride are required per 100ml of water?

Physiological saline, also known as normal saline, is typically a solution that contains 0.9% sodium chloride (NaCl) in water. This concentration is isotonic with the body's fluids, making it suitable for various medical applications, including hydration and as a vehicle for medications.

When preparing a solution of 0.9% NaCl, the calculation is based on the weight of NaCl per 100 mL of water. Specifically, 0.9 grams of NaCl is equivalent to 0.9% w/v (weight/volume). Therefore, to prepare 100 mL of this saline solution, you would need to dissolve 0.9 grams of sodium chloride.

In the context of the options provided, 0.85 grams is closest to this requirement, as it approximates the necessary amount of sodium chloride needed for creating a physiological saline. However, the correct value is conventionally recognized as 0.9 grams, taking into account rounding and standard practices in clinical settings.

Understanding these calculations is crucial for anyone working in a laboratory or clinical environment, ensuring proper formulation of saline solutions that are safe and effective for patient care.