Final answer:
Using the sodium chloride equivalent method, the isotonic concentration of ephedrine sulfate was calculated, and then used to determine the mass of NaCl needed. However, the result did not match the given options, suggesting a possible error or incorrect provided options.
Step-by-step explanation:
The student has asked to calculate the number of grams of NaCl required to prepare 50 mL of isotonic solution of 2% ephedrine sulfate. The ephedrine sulfate has a molecular weight of 428.54 g/mole and an isotonic coefficient (Liso) of 5.8. Using the sodium chloride equivalent method, we first calculate the isotonic concentration of ephedrine sulfate:
Isotonic concentration = (Percent strength of ephedrine sulfate x MW of ephedrine sulfate) / (58.5 x Liso of ephedrine sulfate)
Isotonic concentration = (2 g/100 mL x 428.54 g/mole) / (58.5 x 5.8) = 0.2514 g/mole
To find the amount of NaCl for the isotonic solution, we multiply the isotonic concentration by the volume of the solution and the molecular weight of NaCl:
Mass of NaCl = Isotonic concentration x Volume x MW of NaCl
Mass of NaCl = 0.2514 g/mole x 50 mL / 1000 mL/L x 58.44 g/mole = 0.73 g
However, the quantity calculated does not match any of the options provided (a) 0.22 g, b) 0.58 g, c) 1.0 g, d) 0.02 g). There may have been an error in the computation or the provided options may be incorrect. The student should verify the values and recalculate or consult their instructor for clarification.