Question

Two binary solutions have the same molarity. Which of the following statements is true?

• A. Equal volumes of the two solutions contain equal number of solute molecules.
• B. Equal weights of the two solutions contain equal number of solute molecules.
• C. The two solutions, must have the same molality.
• D. The two solutions must have the same mole fraction.

Answer 1

Answer: (A)

Molarity $=\frac{w}{M\times V}$

For two solutions having same molarity,

$\frac{w_1}{M_1\times V_1}=\frac{w_2}{M_2\times V_2}$

If $V_1=V_2,\frac{w_1}{M_1}=\frac{w_2}{M_2}$

Thus, solutions contain equal no. of moles of solute and hence equal no. of molecules