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 $\mathrm{g} ~\mathrm{mol}^{-1}$ for ethylene glycol $62, \mathrm{~K}_f$ of water $=1.86 \mathrm{~K}$ $\mathrm{kg} ~\mathrm{mol}^{-1}$ )