Question

A 5% solution of glucose (molar mass 180) is isotonic with a 2.5% solution of substance X at the same temperature. The molar mass of X is

• A. 90
• B. 45
• C. 180
• D. 360

Answer 1

Answer: (A)

90

Answer 2

$\frac{5}{180} = \frac{2.5}{x} or x = \frac{2.5 \times 180}{5} = 90$