How many grams of NaCl are needed to prepare 500mL of a 0.9% (w/v) solution? A 9 g B 4.5 g C 0.9 g D 45 g ✓ Correct Answer: Option B 0.9% w/v = 0.9g per 100mL. For 500mL: 0.9 × 5 = 4.5g. Practice PCAT Exam Prep Quizzes → Browse All Questions Study Flashcards