Question

The volume of ethanol required to prepare 3 L of 0.25 M aqueous solution is (density of ethanol = 0.36 kg L\(^{-1}\), molar mass = 60 g mol\(^{-1}\)):

• A. 125 mL
• B. 25 mL
• C. 75 mL
• D. 50 mL
• E. 12.5 mL

Hint:

To find the volume of a substance, use the relation: \({Volume} = \frac{{Mass}}{{Density}}\).

Answer 1

The Correct Option is A

First, find the moles of ethanol required: \[ \text{Moles of ethanol} = M \times V = 0.25\, \text{mol/L} \times 3\, \text{L} = 0.75\, \text{mol} \] Now, calculate the mass of ethanol: \[ \text{Mass} = \text{moles} \times \text{molar mass} = 0.75 \times 60 = 45\, \text{g} \] Using the density formula, find the volume: \[ \text{Volume} = \frac{{\text{Mass}}}{{\text{Density}}} = \frac{45}{0.36} = 125\, \text{mL} \] Thus, the required volume of ethanol is 125 mL.