Solutions Question 2
Question 2 - 2024 (01 Feb Shift 2)
Mass of ethylene glycol (antifreeze) to be added to $18.6 \mathrm{~kg}$ of water to protect the freezing point at $-24^{\circ} \mathrm{C}$ is __________ $\mathrm{kg}$ (Molar mass in $\mathrm{gmol}^{-1}$ for ethylene glycol $62, \mathrm{~K}_{\mathrm{f}}$ of water $=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ )
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Answer (15)
Solution
$\Delta \mathrm{T}{\mathrm{f}}=\mathrm{iK}{\mathrm{f}} \times$ molality
$24=(1) \times 1.86 \times \frac{\mathrm{W}}{62 \times 18.6}$
$\mathrm{W}=14880 \mathrm{gm}$
$=14.880 \mathrm{~kg}$
