Question

A 1 % aqueous solution (M/V) of a certain substance is isotonic with a 3 % solution of glucose (M. Mass 180). The molar mass of the substance is

• A. 60
• B. 120
• C. 180
• D. 360

Answer 1

Answer: (A)

60

Answer 2

For isotonic solutions . $\frac{n_1}{V_1} = \frac{n_2}{V_2}$ $\frac{m_1}{M_1 \times V_1} = \frac{m_2}{M_2 \times V_2}$ $\frac{1}{M_1 \times 100} = \frac{3}{180 \times 100}$ $M_1 = 60$