OnlineCBT
Chemistry · Some Basic Concepts of Chemistry
हिन्दीCalculate the molarity of a solution of ethanol in water, in which the mole fraction of ethanol is \( 0.040 \) (assume the density of water to be \( 1\text{ g mL}^{-1} \)).
Correct answer · Option 4
2.32 mol L⁻¹
Explanation
In \( 1000\text{ g} \) of water, moles = \( 55.56 \). Since \( x_B = 0.040 \), \( n_B = 55.56 \times \frac{0.040}{0.960} = 2.315\text{ mol} \) in \( 1\text{ kg} \) water. Volume \( \approx 1\text{ L} \), so molarity is \( 2.32\text{ mol L}^{-1} \).
