Question

Ethylene glycol is used as antifreeze to reduce freezing point of water to $-2.4^{\circ}\,C$. What mass of antifreeze is required for $2\, L$ water? $(K_f \,water\, = \,1.86\, K \,kg/mole)$

• A. 16 kg
• B. 160 g
• C. 1.60 kg
• D. 16 g

Answer 1

Answer: (B)

160 g

Answer 2

$w_{solute}=\frac{\Delta T _{f} \times w_{water}\times M_{solute}}{K _{f}}$ $\quad\quad=\frac{2.4\times2\times0.062}{1.86}=160 g$ $\quad\quad\quad\quad$ [Mass of 2 L of water is 2 kg.]