Question

in cold climate water gets frozen causing damage to rotation of car. ethylene glycol is used as antifreezing agent. calculate the amount of ethylene glycol to be added to 4 kg of water to prevent it from freezing at -6c

Answer 1

Molar mass of ethylene glycol = 62 g/mol
$∆{\mathrm{T}}_{\mathrm{f}}=0°-(-6°)=6°\mathrm{C}\mathrm{or}6\mathrm{K}$

M_solute = $\frac{\mathrm{Kf}\times {\mathrm{W}}_{\mathrm{solute}}\times 1000}{∆\mathrm{Tf}\times {\mathrm{W}}_{\mathrm{solvent}}}$

W_solute = $\frac{{\mathrm{M}}_{\mathrm{solute}}\times ∆{\mathrm{T}}_{\mathrm{f}}\times {\mathrm{W}}_{\mathrm{solvent}}}{{\mathrm{K}}_{\mathrm{f}}\times 1000}=\frac{32\mathrm{g}{\mathrm{mol}}^{-1}\times 6\mathrm{K}\times 4000\mathrm{g}}{1.85\mathrm{K}{\mathrm{mol}}^{-1}\times 1000}=415.13\mathrm{g}$